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4<head>
Reid Spencer9bbba0912004-11-16 06:11:52 +0000[diff] [blame]5 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]6 <title>CommandLine 2.0 Library Manual</title>
Misha Brukman3c299112003-11-07 18:11:14 +0000[diff] [blame]7 <link rel="stylesheet" href="llvm.css" type="text/css">
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]8</head>
9<body>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]10
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]11<div class="doc_title">
12 CommandLine 2.0 Library Manual
13</div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]14
15<ol>
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]16 <li><a href="#introduction">Introduction</a></li>
17
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]18 <li><a href="#quickstart">Quick Start Guide</a>
19 <ol>
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]20 <li><a href="#bool">Boolean Arguments</a></li>
21 <li><a href="#alias">Argument Aliases</a></li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]22 <li><a href="#onealternative">Selecting an alternative from a
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]23 set of possibilities</a></li>
24 <li><a href="#namedalternatives">Named alternatives</a></li>
25 <li><a href="#list">Parsing a list of options</a></li>
Jim Laskey1d8f6262005-08-25 22:52:43 +0000[diff] [blame]26 <li><a href="#bits">Collecting options as a set of flags</a></li>
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]27 <li><a href="#description">Adding freeform text to help output</a></li>
28 </ol></li>
29
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]30 <li><a href="#referenceguide">Reference Guide</a>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]31 <ol>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]32 <li><a href="#positional">Positional Arguments</a>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]33 <ul>
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]34 <li><a href="#--">Specifying positional options with hyphens</a></li>
Reid Spencer2c8ab582004-08-13 20:19:14 +0000[diff] [blame]35 <li><a href="#getPosition">Determining absolute position with
36 getPosition</a></li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]37 <li><a href="#cl::ConsumeAfter">The <tt>cl::ConsumeAfter</tt>
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]38 modifier</a></li>
39 </ul></li>
40
41 <li><a href="#storage">Internal vs External Storage</a></li>
42
43 <li><a href="#attributes">Option Attributes</a></li>
44
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]45 <li><a href="#modifiers">Option Modifiers</a>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]46 <ul>
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]47 <li><a href="#hiding">Hiding an option from <tt>--help</tt>
48 output</a></li>
49 <li><a href="#numoccurrences">Controlling the number of occurrences
50 required and allowed</a></li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]51 <li><a href="#valrequired">Controlling whether or not a value must be
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]52 specified</a></li>
53 <li><a href="#formatting">Controlling other formatting options</a></li>
54 <li><a href="#misc">Miscellaneous option modifiers</a></li>
55 </ul></li>
56
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]57 <li><a href="#toplevel">Top-Level Classes and Functions</a>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]58 <ul>
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]59 <li><a href="#cl::ParseCommandLineOptions">The
60 <tt>cl::ParseCommandLineOptions</tt> function</a></li>
61 <li><a href="#cl::ParseEnvironmentOptions">The
62 <tt>cl::ParseEnvironmentOptions</tt> function</a></li>
Reid Spencer2403b852006-06-05 17:30:16 +0000[diff] [blame]63 <li><a href="#cl::SetVersionPrinter">The cl::SetVersionPrinter
64 function</a></li>
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]65 <li><a href="#cl::opt">The <tt>cl::opt</tt> class</a></li>
66 <li><a href="#cl::list">The <tt>cl::list</tt> class</a></li>
Jim Laskey1d8f6262005-08-25 22:52:43 +0000[diff] [blame]67 <li><a href="#cl::bits">The <tt>cl::bits</tt> class</a></li>
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]68 <li><a href="#cl::alias">The <tt>cl::alias</tt> class</a></li>
Reid Spencer9bbba0912004-11-16 06:11:52 +0000[diff] [blame]69 <li><a href="#cl::extrahelp">The <tt>cl::extrahelp</tt> class</a></li>
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]70 </ul></li>
71
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]72 <li><a href="#builtinparsers">Builtin parsers</a>
73 <ul>
74 <li><a href="#genericparser">The Generic <tt>parser&lt;t&gt;</tt>
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]75 parser</a></li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]76 <li><a href="#boolparser">The <tt>parser&lt;bool&gt;</tt>
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]77 specialization</a></li>
Dale Johannesen0f2c8fc2007-05-22 18:32:34 +0000[diff] [blame^]78 <li><a href="#boolOrDefaultparser">The <tt>parser&lt;boolOrDefault&gt;</tt>
79 specialization</a></li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]80 <li><a href="#stringparser">The <tt>parser&lt;string&gt;</tt>
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]81 specialization</a></li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]82 <li><a href="#intparser">The <tt>parser&lt;int&gt;</tt>
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]83 specialization</a></li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]84 <li><a href="#doubleparser">The <tt>parser&lt;double&gt;</tt> and
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]85 <tt>parser&lt;float&gt;</tt> specializations</a></li>
86 </ul></li>
87 </ol></li>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]88 <li><a href="#extensionguide">Extension Guide</a>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]89 <ol>
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]90 <li><a href="#customparser">Writing a custom parser</a></li>
91 <li><a href="#explotingexternal">Exploiting external storage</a></li>
92 <li><a href="#dynamicopts">Dynamically adding command line
93 options</a></li>
94 </ol></li>
95</ol>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]96
Chris Lattner7911ce22004-05-23 21:07:27 +0000[diff] [blame]97<div class="doc_author">
98 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a></p>
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]99</div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]100
101<!-- *********************************************************************** -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]102<div class="doc_section">
Misha Brukman8becd712003-11-07 19:42:44 +0000[diff] [blame]103 <a name="introduction">Introduction</a>
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]104</div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]105<!-- *********************************************************************** -->
106
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]107<div class="doc_text">
108
109<p>This document describes the CommandLine argument processing library. It will
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]110show you how to use it, and what it can do. The CommandLine library uses a
111declarative approach to specifying the command line options that your program
112takes. By default, these options declarations implicitly hold the value parsed
113for the option declared (of course this <a href="#storage">can be
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]114changed</a>).</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]115
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]116<p>Although there are a <b>lot</b> of command line argument parsing libraries
117out there in many different languages, none of them fit well with what I needed.
118By looking at the features and problems of other libraries, I designed the
119CommandLine library to have the following features:</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]120
121<ol>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]122<li>Speed: The CommandLine library is very quick and uses little resources. The
123parsing time of the library is directly proportional to the number of arguments
124parsed, not the the number of options recognized. Additionally, command line
Chris Lattneredf351f2003-06-21 21:45:56 +0000[diff] [blame]125argument values are captured transparently into user defined global variables,
126which can be accessed like any other variable (and with the same
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]127performance).</li>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]128
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]129<li>Type Safe: As a user of CommandLine, you don't have to worry about
130remembering the type of arguments that you want (is it an int? a string? a
131bool? an enum?) and keep casting it around. Not only does this help prevent
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]132error prone constructs, it also leads to dramatically cleaner source code.</li>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]133
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]134<li>No subclasses required: To use CommandLine, you instantiate variables that
135correspond to the arguments that you would like to capture, you don't subclass a
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]136parser. This means that you don't have to write <b>any</b> boilerplate
137code.</li>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]138
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]139<li>Globally accessible: Libraries can specify command line arguments that are
140automatically enabled in any tool that links to the library. This is possible
141because the application doesn't have to keep a "list" of arguments to pass to
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]142the parser. This also makes supporting <a href="#dynamicopts">dynamically
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]143loaded options</a> trivial.</li>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]144
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]145<li>Cleaner: CommandLine supports enum and other types directly, meaning that
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]146there is less error and more security built into the library. You don't have to
147worry about whether your integral command line argument accidentally got
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]148assigned a value that is not valid for your enum type.</li>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]149
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]150<li>Powerful: The CommandLine library supports many different types of
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]151arguments, from simple <a href="#boolparser">boolean flags</a> to <a
152href="#cl::opt">scalars arguments</a> (<a href="#stringparser">strings</a>, <a
153href="#intparser">integers</a>, <a href="#genericparser">enums</a>, <a
154href="#doubleparser">doubles</a>), to <a href="#cl::list">lists of
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]155arguments</a>. This is possible because CommandLine is...</li>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]156
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]157<li>Extensible: It is very simple to add a new argument type to CommandLine.
158Simply specify the parser that you want to use with the command line option when
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]159you declare it. <a href="#customparser">Custom parsers</a> are no problem.</li>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]160
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]161<li>Labor Saving: The CommandLine library cuts down on the amount of grunt work
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]162that you, the user, have to do. For example, it automatically provides a
163<tt>--help</tt> option that shows the available command line options for your
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]164tool. Additionally, it does most of the basic correctness checking for
165you.</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]166
167<li>Capable: The CommandLine library can handle lots of different forms of
168options often found in real programs. For example, <a
169href="#positional">positional</a> arguments, <tt>ls</tt> style <a
170href="#cl::Grouping">grouping</a> options (to allow processing '<tt>ls
171-lad</tt>' naturally), <tt>ld</tt> style <a href="#cl::Prefix">prefix</a>
172options (to parse '<tt>-lmalloc -L/usr/lib</tt>'), and <a
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]173href="#cl::ConsumeAfter">interpreter style options</a>.</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]174
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]175</ol>
176
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]177<p>This document will hopefully let you jump in and start using CommandLine in
178your utility quickly and painlessly. Additionally it should be a simple
179reference manual to figure out how stuff works. If it is failing in some area
180(or you want an extension to the library), nag the author, <a
181href="mailto:sabre@nondot.org">Chris Lattner</a>.</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]182
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]183</div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]184
185<!-- *********************************************************************** -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]186<div class="doc_section">
187 <a name="quickstart">Quick Start Guide</a>
188</div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]189<!-- *********************************************************************** -->
190
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]191<div class="doc_text">
192
193<p>This section of the manual runs through a simple CommandLine'ification of a
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]194basic compiler tool. This is intended to show you how to jump into using the
195CommandLine library in your own program, and show you some of the cool things it
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]196can do.</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]197
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]198<p>To start out, you need to include the CommandLine header file into your
199program:</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]200
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]201<div class="doc_code"><pre>
Andrew Lenharth94f3d1a2005-11-14 19:32:05 +0000[diff] [blame]202 #include "llvm/Support/CommandLine.h"
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]203</pre></div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]204
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]205<p>Additionally, you need to add this as the first line of your main
206program:</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]207
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]208<div class="doc_code"><pre>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]209int main(int argc, char **argv) {
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]210 <a href="#cl::ParseCommandLineOptions">cl::ParseCommandLineOptions</a>(argc, argv);
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]211 ...
212}
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]213</pre></div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]214
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]215<p>... which actually parses the arguments and fills in the variable
216declarations.</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]217
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]218<p>Now that you are ready to support command line arguments, we need to tell the
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]219system which ones we want, and what type of argument they are. The CommandLine
Chris Lattneredf351f2003-06-21 21:45:56 +0000[diff] [blame]220library uses a declarative syntax to model command line arguments with the
221global variable declarations that capture the parsed values. This means that
222for every command line option that you would like to support, there should be a
223global variable declaration to capture the result. For example, in a compiler,
224we would like to support the unix standard '<tt>-o &lt;filename&gt;</tt>' option
225to specify where to put the output. With the CommandLine library, this is
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]226represented like this:</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]227
Misha Brukmanc53aefb2004-05-12 18:42:35 +0000[diff] [blame]228<a name="value_desc_example"></a>
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]229<div class="doc_code"><pre>
Misha Brukmanc53aefb2004-05-12 18:42:35 +0000[diff] [blame]230<a href="#cl::opt">cl::opt</a>&lt;string&gt; OutputFilename("<i>o</i>", <a href="#cl::desc">cl::desc</a>("<i>Specify output filename</i>"), <a href="#cl::value_desc">cl::value_desc</a>("<i>filename</i>"));
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]231</pre></div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]232
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]233<p>This declares a global variable "<tt>OutputFilename</tt>" that is used to
Chris Lattneredf351f2003-06-21 21:45:56 +0000[diff] [blame]234capture the result of the "<tt>o</tt>" argument (first parameter). We specify
235that this is a simple scalar option by using the "<tt><a
236href="#cl::opt">cl::opt</a></tt>" template (as opposed to the <a
237href="#list">"<tt>cl::list</tt> template</a>), and tell the CommandLine library
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]238that the data type that we are parsing is a string.</p>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]239
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]240<p>The second and third parameters (which are optional) are used to specify what
241to output for the "<tt>--help</tt>" option. In this case, we get a line that
242looks like this:</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]243
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]244<div class="doc_code"><pre>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]245USAGE: compiler [options]
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]246
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]247OPTIONS:
248 -help - display available options (--help-hidden for more)
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]249 <b>-o &lt;filename&gt; - Specify output filename</b>
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]250</pre></div>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]251
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]252<p>Because we specified that the command line option should parse using the
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]253<tt>string</tt> data type, the variable declared is automatically usable as a
254real string in all contexts that a normal C++ string object may be used. For
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]255example:</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]256
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]257<div class="doc_code"><pre>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]258 ...
259 ofstream Output(OutputFilename.c_str());
260 if (Out.good()) ...
261 ...
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]262</pre></div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]263
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]264<p>There are many different options that you can use to customize the command
265line option handling library, but the above example shows the general interface
266to these options. The options can be specified in any order, and are specified
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]267with helper functions like <a href="#cl::desc"><tt>cl::desc(...)</tt></a>, so
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]268there are no positional dependencies to remember. The available options are
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]269discussed in detail in the <a href="#referenceguide">Reference Guide</a>.</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]270
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]271<p>Continuing the example, we would like to have our compiler take an input
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]272filename as well as an output filename, but we do not want the input filename to
273be specified with a hyphen (ie, not <tt>-filename.c</tt>). To support this
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]274style of argument, the CommandLine library allows for <a
275href="#positional">positional</a> arguments to be specified for the program.
276These positional arguments are filled with command line parameters that are not
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]277in option form. We use this feature like this:</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]278
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]279<div class="doc_code"><pre>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]280<a href="#cl::opt">cl::opt</a>&lt;string&gt; InputFilename(<a href="#cl::Positional">cl::Positional</a>, <a href="#cl::desc">cl::desc</a>("<i>&lt;input file&gt;</i>"), <a href="#cl::init">cl::init</a>("<i>-</i>"));
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]281</pre></div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]282
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]283<p>This declaration indicates that the first positional argument should be
284treated as the input filename. Here we use the <tt><a
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]285href="#cl::init">cl::init</a></tt> option to specify an initial value for the
286command line option, which is used if the option is not specified (if you do not
287specify a <tt><a href="#cl::init">cl::init</a></tt> modifier for an option, then
288the default constructor for the data type is used to initialize the value).
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]289Command line options default to being optional, so if we would like to require
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]290that the user always specify an input filename, we would add the <tt><a
291href="#cl::Required">cl::Required</a></tt> flag, and we could eliminate the
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]292<tt><a href="#cl::init">cl::init</a></tt> modifier, like this:</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]293
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]294<div class="doc_code"><pre>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]295<a href="#cl::opt">cl::opt</a>&lt;string&gt; InputFilename(<a href="#cl::Positional">cl::Positional</a>, <a href="#cl::desc">cl::desc</a>("<i>&lt;input file&gt;</i>"), <b><a href="#cl::Required">cl::Required</a></b>);
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]296</pre></div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]297
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]298<p>Again, the CommandLine library does not require the options to be specified
299in any particular order, so the above declaration is equivalent to:</p>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]300
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]301<div class="doc_code"><pre>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]302<a href="#cl::opt">cl::opt</a>&lt;string&gt; InputFilename(<a href="#cl::Positional">cl::Positional</a>, <a href="#cl::Required">cl::Required</a>, <a href="#cl::desc">cl::desc</a>("<i>&lt;input file&gt;</i>"));
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]303</pre></div>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]304
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]305<p>By simply adding the <tt><a href="#cl::Required">cl::Required</a></tt> flag,
306the CommandLine library will automatically issue an error if the argument is not
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]307specified, which shifts all of the command line option verification code out of
308your application into the library. This is just one example of how using flags
309can alter the default behaviour of the library, on a per-option basis. By
310adding one of the declarations above, the <tt>--help</tt> option synopsis is now
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]311extended to:</p>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]312
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]313<div class="doc_code"><pre>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]314USAGE: compiler [options] <b>&lt;input file&gt;</b>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]315
316OPTIONS:
317 -help - display available options (--help-hidden for more)
318 -o &lt;filename&gt; - Specify output filename
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]319</pre></div>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]320
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]321<p>... indicating that an input filename is expected.</p>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]322
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]323</div>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]324
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]325<!-- ======================================================================= -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]326<div class="doc_subsection">
327 <a name="bool">Boolean Arguments</a>
328</div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]329
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]330<div class="doc_text">
331
332<p>In addition to input and output filenames, we would like the compiler example
333to support three boolean flags: "<tt>-f</tt>" to force overwriting of the output
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]334file, "<tt>--quiet</tt>" to enable quiet mode, and "<tt>-q</tt>" for backwards
335compatibility with some of our users. We can support these by declaring options
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]336of boolean type like this:</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]337
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]338<div class="doc_code"><pre>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]339<a href="#cl::opt">cl::opt</a>&lt;bool&gt; Force ("<i>f</i>", <a href="#cl::desc">cl::desc</a>("<i>Overwrite output files</i>"));
340<a href="#cl::opt">cl::opt</a>&lt;bool&gt; Quiet ("<i>quiet</i>", <a href="#cl::desc">cl::desc</a>("<i>Don't print informational messages</i>"));
341<a href="#cl::opt">cl::opt</a>&lt;bool&gt; Quiet2("<i>q</i>", <a href="#cl::desc">cl::desc</a>("<i>Don't print informational messages</i>"), <a href="#cl::Hidden">cl::Hidden</a>);
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]342</pre></div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]343
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]344<p>This does what you would expect: it declares three boolean variables
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]345("<tt>Force</tt>", "<tt>Quiet</tt>", and "<tt>Quiet2</tt>") to recognize these
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]346options. Note that the "<tt>-q</tt>" option is specified with the "<a
347href="#cl::Hidden"><tt>cl::Hidden</tt></a>" flag. This modifier prevents it
348from being shown by the standard "<tt>--help</tt>" output (note that it is still
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]349shown in the "<tt>--help-hidden</tt>" output).</p>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]350
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]351<p>The CommandLine library uses a <a href="#builtinparsers">different parser</a>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]352for different data types. For example, in the string case, the argument passed
353to the option is copied literally into the content of the string variable... we
354obviously cannot do that in the boolean case, however, so we must use a smarter
355parser. In the case of the boolean parser, it allows no options (in which case
356it assigns the value of true to the variable), or it allows the values
357"<tt>true</tt>" or "<tt>false</tt>" to be specified, allowing any of the
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]358following inputs:</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]359
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]360<div class="doc_code"><pre>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]361 compiler -f # No value, 'Force' == true
362 compiler -f=true # Value specified, 'Force' == true
363 compiler -f=TRUE # Value specified, 'Force' == true
364 compiler -f=FALSE # Value specified, 'Force' == false
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]365</pre></div>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]366
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]367<p>... you get the idea. The <a href="#boolparser">bool parser</a> just turns
368the string values into boolean values, and rejects things like '<tt>compiler
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]369-f=foo</tt>'. Similarly, the <a href="#doubleparser">float</a>, <a
370href="#doubleparser">double</a>, and <a href="#intparser">int</a> parsers work
371like you would expect, using the '<tt>strtol</tt>' and '<tt>strtod</tt>' C
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]372library calls to parse the string value into the specified data type.</p>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]373
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]374<p>With the declarations above, "<tt>compiler --help</tt>" emits this:</p>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]375
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]376<div class="doc_code"><pre>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]377USAGE: compiler [options] &lt;input file&gt;
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]378
379OPTIONS:
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]380 <b>-f - Overwrite output files</b>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]381 -o - Override output filename
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]382 <b>-quiet - Don't print informational messages</b>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]383 -help - display available options (--help-hidden for more)
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]384</pre></div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]385
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]386<p>and "<tt>opt --help-hidden</tt>" prints this:</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]387
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]388<div class="doc_code"><pre>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]389USAGE: compiler [options] &lt;input file&gt;
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]390
391OPTIONS:
392 -f - Overwrite output files
393 -o - Override output filename
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]394 <b>-q - Don't print informational messages</b>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]395 -quiet - Don't print informational messages
396 -help - display available options (--help-hidden for more)
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]397</pre></div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]398
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]399<p>This brief example has shown you how to use the '<tt><a
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]400href="#cl::opt">cl::opt</a></tt>' class to parse simple scalar command line
401arguments. In addition to simple scalar arguments, the CommandLine library also
402provides primitives to support CommandLine option <a href="#alias">aliases</a>,
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]403and <a href="#list">lists</a> of options.</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]404
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]405</div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]406
407<!-- ======================================================================= -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]408<div class="doc_subsection">
409 <a name="alias">Argument Aliases</a>
410</div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]411
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]412<div class="doc_text">
413
414<p>So far, the example works well, except for the fact that we need to check the
415quiet condition like this now:</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]416
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]417<div class="doc_code"><pre>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]418...
419 if (!Quiet &amp;&amp; !Quiet2) printInformationalMessage(...);
420...
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]421</pre></div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]422
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]423<p>... which is a real pain! Instead of defining two values for the same
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]424condition, we can use the "<tt><a href="#cl::alias">cl::alias</a></tt>" class to make the "<tt>-q</tt>"
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]425option an <b>alias</b> for the "<tt>-quiet</tt>" option, instead of providing
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]426a value itself:</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]427
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]428<div class="doc_code"><pre>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]429<a href="#cl::opt">cl::opt</a>&lt;bool&gt; Force ("<i>f</i>", <a href="#cl::desc">cl::desc</a>("<i>Overwrite output files</i>"));
430<a href="#cl::opt">cl::opt</a>&lt;bool&gt; Quiet ("<i>quiet</i>", <a href="#cl::desc">cl::desc</a>("<i>Don't print informational messages</i>"));
431<a href="#cl::alias">cl::alias</a> QuietA("<i>q</i>", <a href="#cl::desc">cl::desc</a>("<i>Alias for -quiet</i>"), <a href="#cl::aliasopt">cl::aliasopt</a>(Quiet));
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]432</pre></div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]433
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]434<p>The third line (which is the only one we modified from above) defines a
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]435"<tt>-q</tt> alias that updates the "<tt>Quiet</tt>" variable (as specified by
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]436the <tt><a href="#cl::aliasopt">cl::aliasopt</a></tt> modifier) whenever it is
437specified. Because aliases do not hold state, the only thing the program has to
438query is the <tt>Quiet</tt> variable now. Another nice feature of aliases is
439that they automatically hide themselves from the <tt>-help</tt> output
440(although, again, they are still visible in the <tt>--help-hidden
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]441output</tt>).</p>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]442
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]443<p>Now the application code can simply use:</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]444
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]445<div class="doc_code"><pre>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]446...
447 if (!Quiet) printInformationalMessage(...);
448...
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]449</pre></div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]450
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]451<p>... which is much nicer! The "<tt><a href="#cl::alias">cl::alias</a></tt>"
452can be used to specify an alternative name for any variable type, and has many
453uses.</p>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]454
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]455</div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]456
457<!-- ======================================================================= -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]458<div class="doc_subsection">
459 <a name="onealternative">Selecting an alternative from a set of
460 possibilities</a>
461</div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]462
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]463<div class="doc_text">
464
465<p>So far, we have seen how the CommandLine library handles builtin types like
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]466<tt>std::string</tt>, <tt>bool</tt> and <tt>int</tt>, but how does it handle
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]467things it doesn't know about, like enums or '<tt>int*</tt>'s?</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]468
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]469<p>The answer is that it uses a table driven generic parser (unless you specify
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]470your own parser, as described in the <a href="#extensionguide">Extension
Reid Spencerd8473372004-08-10 16:38:18 +0000[diff] [blame]471Guide</a>). This parser maps literal strings to whatever type is required, and
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]472requires you to tell it what this mapping should be.</p>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]473
Reid Spencerd8473372004-08-10 16:38:18 +0000[diff] [blame]474<p>Lets say that we would like to add four optimization levels to our
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]475optimizer, using the standard flags "<tt>-g</tt>", "<tt>-O0</tt>",
476"<tt>-O1</tt>", and "<tt>-O2</tt>". We could easily implement this with boolean
477options like above, but there are several problems with this strategy:</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]478
479<ol>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]480<li>A user could specify more than one of the options at a time, for example,
481"<tt>opt -O3 -O2</tt>". The CommandLine library would not be able to catch this
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]482erroneous input for us.</li>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]483
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]484<li>We would have to test 4 different variables to see which ones are set.</li>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]485
486<li>This doesn't map to the numeric levels that we want... so we cannot easily
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]487see if some level &gt;= "<tt>-O1</tt>" is enabled.</li>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]488
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]489</ol>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]490
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]491<p>To cope with these problems, we can use an enum value, and have the
492CommandLine library fill it in with the appropriate level directly, which is
493used like this:</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]494
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]495<div class="doc_code"><pre>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]496enum OptLevel {
497 g, O1, O2, O3
498};
499
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]500<a href="#cl::opt">cl::opt</a>&lt;OptLevel&gt; OptimizationLevel(<a href="#cl::desc">cl::desc</a>("<i>Choose optimization level:</i>"),
501 <a href="#cl::values">cl::values</a>(
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]502 clEnumVal(g , "<i>No optimizations, enable debugging</i>"),
503 clEnumVal(O1, "<i>Enable trivial optimizations</i>"),
504 clEnumVal(O2, "<i>Enable default optimizations</i>"),
505 clEnumVal(O3, "<i>Enable expensive optimizations</i>"),
Chris Lattnerb406ead2004-07-16 00:10:54 +0000[diff] [blame]506 clEnumValEnd));
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]507
508...
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]509 if (OptimizationLevel &gt;= O2) doPartialRedundancyElimination(...);
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]510...
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]511</pre></div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]512
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]513<p>This declaration defines a variable "<tt>OptimizationLevel</tt>" of the
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]514"<tt>OptLevel</tt>" enum type. This variable can be assigned any of the values
515that are listed in the declaration (Note that the declaration list must be
Chris Lattnerb406ead2004-07-16 00:10:54 +0000[diff] [blame]516terminated with the "<tt>clEnumValEnd</tt>" argument!). The CommandLine
517library enforces
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]518that the user can only specify one of the options, and it ensure that only valid
519enum values can be specified. The "<tt>clEnumVal</tt>" macros ensure that the
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]520command line arguments matched the enum values. With this option added, our
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]521help output now is:</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]522
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]523<div class="doc_code"><pre>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]524USAGE: compiler [options] &lt;input file&gt;
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]525
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]526OPTIONS:
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]527 <b>Choose optimization level:
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]528 -g - No optimizations, enable debugging
529 -O1 - Enable trivial optimizations
530 -O2 - Enable default optimizations
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]531 -O3 - Enable expensive optimizations</b>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]532 -f - Overwrite output files
533 -help - display available options (--help-hidden for more)
534 -o &lt;filename&gt; - Specify output filename
535 -quiet - Don't print informational messages
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]536</pre></div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]537
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]538<p>In this case, it is sort of awkward that flag names correspond directly to
539enum names, because we probably don't want a enum definition named "<tt>g</tt>"
540in our program. Because of this, we can alternatively write this example like
541this:</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]542
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]543<div class="doc_code"><pre>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]544enum OptLevel {
545 Debug, O1, O2, O3
546};
547
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]548<a href="#cl::opt">cl::opt</a>&lt;OptLevel&gt; OptimizationLevel(<a href="#cl::desc">cl::desc</a>("<i>Choose optimization level:</i>"),
549 <a href="#cl::values">cl::values</a>(
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]550 clEnumValN(Debug, "g", "<i>No optimizations, enable debugging</i>"),
551 clEnumVal(O1 , "<i>Enable trivial optimizations</i>"),
552 clEnumVal(O2 , "<i>Enable default optimizations</i>"),
553 clEnumVal(O3 , "<i>Enable expensive optimizations</i>"),
Chris Lattnerb406ead2004-07-16 00:10:54 +0000[diff] [blame]554 clEnumValEnd));
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]555
556...
557 if (OptimizationLevel == Debug) outputDebugInfo(...);
558...
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]559</pre></div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]560
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]561<p>By using the "<tt>clEnumValN</tt>" macro instead of "<tt>clEnumVal</tt>", we
562can directly specify the name that the flag should get. In general a direct
563mapping is nice, but sometimes you can't or don't want to preserve the mapping,
564which is when you would use it.</p>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]565
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]566</div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]567
568<!-- ======================================================================= -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]569<div class="doc_subsection">
570 <a name="namedalternatives">Named Alternatives</a>
571</div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]572
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]573<div class="doc_text">
574
575<p>Another useful argument form is a named alternative style. We shall use this
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]576style in our compiler to specify different debug levels that can be used.
577Instead of each debug level being its own switch, we want to support the
578following options, of which only one can be specified at a time:
579"<tt>--debug-level=none</tt>", "<tt>--debug-level=quick</tt>",
580"<tt>--debug-level=detailed</tt>". To do this, we use the exact same format as
581our optimization level flags, but we also specify an option name. For this
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]582case, the code looks like this:</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]583
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]584<div class="doc_code"><pre>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]585enum DebugLev {
586 nodebuginfo, quick, detailed
587};
588
589// Enable Debug Options to be specified on the command line
Chris Lattnerdc844fa2003-06-03 04:40:06 +0000[diff] [blame]590<a href="#cl::opt">cl::opt</a>&lt;DebugLev&gt; DebugLevel("<i>debug_level</i>", <a href="#cl::desc">cl::desc</a>("<i>Set the debugging level:</i>"),
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]591 <a href="#cl::values">cl::values</a>(
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]592 clEnumValN(nodebuginfo, "none", "<i>disable debug information</i>"),
593 clEnumVal(quick, "<i>enable quick debug information</i>"),
594 clEnumVal(detailed, "<i>enable detailed debug information</i>"),
Chris Lattnerb406ead2004-07-16 00:10:54 +0000[diff] [blame]595 clEnumValEnd));
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]596</pre></div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]597
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]598<p>This definition defines an enumerated command line variable of type "<tt>enum
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]599DebugLev</tt>", which works exactly the same way as before. The difference here
600is just the interface exposed to the user of your program and the help output by
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]601the "<tt>--help</tt>" option:</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]602
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]603<div class="doc_code"><pre>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]604USAGE: compiler [options] &lt;input file&gt;
605
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]606OPTIONS:
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]607 Choose optimization level:
608 -g - No optimizations, enable debugging
609 -O1 - Enable trivial optimizations
610 -O2 - Enable default optimizations
611 -O3 - Enable expensive optimizations
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]612 <b>-debug_level - Set the debugging level:
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]613 =none - disable debug information
614 =quick - enable quick debug information
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]615 =detailed - enable detailed debug information</b>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]616 -f - Overwrite output files
617 -help - display available options (--help-hidden for more)
618 -o &lt;filename&gt; - Specify output filename
619 -quiet - Don't print informational messages
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]620</pre></div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]621
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]622<p>Again, the only structural difference between the debug level declaration and
John Criswellc24d4822004-11-21 14:34:34 +0000[diff] [blame]623the optimization level declaration is that the debug level declaration includes
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]624an option name (<tt>"debug_level"</tt>), which automatically changes how the
625library processes the argument. The CommandLine library supports both forms so
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]626that you can choose the form most appropriate for your application.</p>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]627
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]628</div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]629
630<!-- ======================================================================= -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]631<div class="doc_subsection">
632 <a name="list">Parsing a list of options</a>
633</div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]634
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]635<div class="doc_text">
636
637<p>Now that we have the standard run of the mill argument types out of the way,
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]638lets get a little wild and crazy. Lets say that we want our optimizer to accept
639a <b>list</b> of optimizations to perform, allowing duplicates. For example, we
640might want to run: "<tt>compiler -dce -constprop -inline -dce -strip</tt>". In
641this case, the order of the arguments and the number of appearances is very
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]642important. This is what the "<tt><a href="#cl::list">cl::list</a></tt>"
643template is for. First, start by defining an enum of the optimizations that you
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]644would like to perform:</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]645
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]646<div class="doc_code"><pre>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]647enum Opts {
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]648 // 'inline' is a C++ keyword, so name it 'inlining'
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]649 dce, constprop, inlining, strip
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]650};
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]651</pre></div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]652
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]653<p>Then define your "<tt><a href="#cl::list">cl::list</a></tt>" variable:</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]654
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]655<div class="doc_code"><pre>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]656<a href="#cl::list">cl::list</a>&lt;Opts&gt; OptimizationList(<a href="#cl::desc">cl::desc</a>("<i>Available Optimizations:</i>"),
657 <a href="#cl::values">cl::values</a>(
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]658 clEnumVal(dce , "<i>Dead Code Elimination</i>"),
Misha Brukman82c89b92003-05-20 21:01:22 +0000[diff] [blame]659 clEnumVal(constprop , "<i>Constant Propagation</i>"),
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]660 clEnumValN(inlining, "<i>inline</i>", "<i>Procedure Integration</i>"),
661 clEnumVal(strip , "<i>Strip Symbols</i>"),
Chris Lattnerb406ead2004-07-16 00:10:54 +0000[diff] [blame]662 clEnumValEnd));
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]663</pre></div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]664
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]665<p>This defines a variable that is conceptually of the type
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]666"<tt>std::vector&lt;enum Opts&gt;</tt>". Thus, you can access it with standard
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]667vector methods:</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]668
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]669<div class="doc_code"><pre>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]670 for (unsigned i = 0; i != OptimizationList.size(); ++i)
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]671 switch (OptimizationList[i])
672 ...
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]673</pre></div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]674
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]675<p>... to iterate through the list of options specified.</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]676
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]677<p>Note that the "<tt><a href="#cl::list">cl::list</a></tt>" template is
678completely general and may be used with any data types or other arguments that
679you can use with the "<tt><a href="#cl::opt">cl::opt</a></tt>" template. One
680especially useful way to use a list is to capture all of the positional
681arguments together if there may be more than one specified. In the case of a
682linker, for example, the linker takes several '<tt>.o</tt>' files, and needs to
683capture them into a list. This is naturally specified as:</p>
Chris Lattner3e5fe172002-04-13 18:35:59 +0000[diff] [blame]684
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]685<div class="doc_code"><pre>
Chris Lattner3e5fe172002-04-13 18:35:59 +0000[diff] [blame]686...
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]687<a href="#cl::list">cl::list</a>&lt;std::string&gt; InputFilenames(<a href="#cl::Positional">cl::Positional</a>, <a href="#cl::desc">cl::desc</a>("&lt;Input files&gt;"), <a href="#cl::OneOrMore">cl::OneOrMore</a>);
Chris Lattner3e5fe172002-04-13 18:35:59 +0000[diff] [blame]688...
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]689</pre></div>
Chris Lattner3e5fe172002-04-13 18:35:59 +0000[diff] [blame]690
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]691<p>This variable works just like a "<tt>vector&lt;string&gt;</tt>" object. As
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]692such, accessing the list is simple, just like above. In this example, we used
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]693the <tt><a href="#cl::OneOrMore">cl::OneOrMore</a></tt> modifier to inform the
694CommandLine library that it is an error if the user does not specify any
695<tt>.o</tt> files on our command line. Again, this just reduces the amount of
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]696checking we have to do.</p>
Chris Lattner3e5fe172002-04-13 18:35:59 +0000[diff] [blame]697
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]698</div>
Chris Lattner3e5fe172002-04-13 18:35:59 +0000[diff] [blame]699
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]700<!-- ======================================================================= -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]701<div class="doc_subsection">
Jim Laskey1d8f6262005-08-25 22:52:43 +0000[diff] [blame]702 <a name="bits">Collecting options as a set of flags</a>
703</div>
704
705<div class="doc_text">
706
707<p>Instead of collecting sets of options in a list, it is also possible to
Jim Laskey22b7dfa2005-08-26 09:25:54 +0000[diff] [blame]708gather information for enum values in a <b>bit vector</b>. The represention used by
709the <a href="#bits"><tt>cl::bits</tt></a> class is an <tt>unsigned</tt>
Jim Laskey1d8f6262005-08-25 22:52:43 +0000[diff] [blame]710integer. An enum value is represented by a 0/1 in the enum's ordinal value bit
711position. 1 indicating that the enum was specified, 0 otherwise. As each
712specified value is parsed, the resulting enum's bit is set in the option's bit
713vector:</p>
714
715<div class="doc_code"><pre>
716 <i>bits</i> |= 1 << (unsigned)<i>enum</i>;
717</pre></div>
718
Jim Laskey26029222005-08-25 23:01:25 +0000[diff] [blame]719<p>Options that are specified multiple times are redundant. Any instances after
720the first are discarded.</p>
Jim Laskey1d8f6262005-08-25 22:52:43 +0000[diff] [blame]721
722<p>Reworking the above list example, we could replace <a href="#list">
723<tt>cl::list</tt></a> with <a href="#bits"><tt>cl::bits</tt></a>:</p>
724
725<div class="doc_code"><pre>
726<a href="#cl::bits">cl::bits</a>&lt;Opts&gt; OptimizationBits(<a href="#cl::desc">cl::desc</a>("<i>Available Optimizations:</i>"),
727 <a href="#cl::values">cl::values</a>(
728 clEnumVal(dce , "<i>Dead Code Elimination</i>"),
729 clEnumVal(constprop , "<i>Constant Propagation</i>"),
730 clEnumValN(inlining, "<i>inline</i>", "<i>Procedure Integration</i>"),
731 clEnumVal(strip , "<i>Strip Symbols</i>"),
732 clEnumValEnd));
733</pre></div>
734
735<p>To test to see if <tt>constprop</tt> was specified, we can use the
736<tt>cl:bits::isSet</tt> function:</p>
737
738<div class="doc_code"><pre>
739 if (OptimizationBits.isSet(constprop)) {
740 ...
741 }
742</pre></div>
743
744<p>It's also possible to get the raw bit vector using the
745<tt>cl::bits::getBits</tt> function:</p>
746
747<div class="doc_code"><pre>
Jim Laskey22b7dfa2005-08-26 09:25:54 +0000[diff] [blame]748 unsigned bits = OptimizationBits.getBits();
Jim Laskey1d8f6262005-08-25 22:52:43 +0000[diff] [blame]749</pre></div>
750
751<p>Finally, if external storage is used, then the location specified must be of
Jim Laskey22b7dfa2005-08-26 09:25:54 +0000[diff] [blame]752<b>type</b> <tt>unsigned</tt>. In all other ways a <a
Jim Laskey1d8f6262005-08-25 22:52:43 +0000[diff] [blame]753href="#bits"><tt>cl::bits</tt></a> option is morally equivalent to a <a
Jim Laskey22b7dfa2005-08-26 09:25:54 +0000[diff] [blame]754href="#list"> <tt>cl::list</tt></a> option.</p>
Jim Laskey1d8f6262005-08-25 22:52:43 +0000[diff] [blame]755
756</div>
757
758
759<!-- ======================================================================= -->
760<div class="doc_subsection">
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]761 <a name="description">Adding freeform text to help output</a>
762</div>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]763
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]764<div class="doc_text">
765
766<p>As our program grows and becomes more mature, we may decide to put summary
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]767information about what it does into the help output. The help output is styled
768to look similar to a Unix <tt>man</tt> page, providing concise information about
769a program. Unix <tt>man</tt> pages, however often have a description about what
770the program does. To add this to your CommandLine program, simply pass a third
771argument to the <a
772href="#cl::ParseCommandLineOptions"><tt>cl::ParseCommandLineOptions</tt></a>
773call in main. This additional argument is then printed as the overview
774information for your program, allowing you to include any additional information
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]775that you want. For example:</p>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]776
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]777<div class="doc_code"><pre>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]778int main(int argc, char **argv) {
779 <a href="#cl::ParseCommandLineOptions">cl::ParseCommandLineOptions</a>(argc, argv, " CommandLine compiler example\n\n"
780 " This program blah blah blah...\n");
781 ...
782}
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]783</pre></div>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]784
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]785<p>would yield the help output:</p>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]786
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]787<div class="doc_code"><pre>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]788<b>OVERVIEW: CommandLine compiler example
789
790 This program blah blah blah...</b>
791
792USAGE: compiler [options] &lt;input file&gt;
793
794OPTIONS:
795 ...
796 -help - display available options (--help-hidden for more)
797 -o &lt;filename&gt; - Specify output filename
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]798</pre></div>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]799
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]800</div>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]801
802
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]803<!-- *********************************************************************** -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]804<div class="doc_section">
805 <a name="referenceguide">Reference Guide</a>
806</div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]807<!-- *********************************************************************** -->
808
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]809<div class="doc_text">
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]810
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]811<p>Now that you know the basics of how to use the CommandLine library, this
812section will give you the detailed information you need to tune how command line
813options work, as well as information on more "advanced" command line option
814processing capabilities.</p>
815
816</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]817
818<!-- ======================================================================= -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]819<div class="doc_subsection">
820 <a name="positional">Positional Arguments</a>
821</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]822
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]823<div class="doc_text">
824
825<p>Positional arguments are those arguments that are not named, and are not
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]826specified with a hyphen. Positional arguments should be used when an option is
827specified by its position alone. For example, the standard Unix <tt>grep</tt>
828tool takes a regular expression argument, and an optional filename to search
829through (which defaults to standard input if a filename is not specified).
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]830Using the CommandLine library, this would be specified as:</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]831
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]832<div class="doc_code"><pre>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]833<a href="#cl::opt">cl::opt</a>&lt;string&gt; Regex (<a href="#cl::Positional">cl::Positional</a>, <a href="#cl::desc">cl::desc</a>("<i>&lt;regular expression&gt;</i>"), <a href="#cl::Required">cl::Required</a>);
834<a href="#cl::opt">cl::opt</a>&lt;string&gt; Filename(<a href="#cl::Positional">cl::Positional</a>, <a href="#cl::desc">cl::desc</a>("<i>&lt;input file&gt;</i>"), <a href="#cl::init">cl::init</a>("<i>-</i>"));
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]835</pre></div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]836
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]837<p>Given these two option declarations, the <tt>--help</tt> output for our grep
838replacement would look like this:</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]839
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]840<div class="doc_code"><pre>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]841USAGE: spiffygrep [options] <b>&lt;regular expression&gt; &lt;input file&gt;</b>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]842
843OPTIONS:
844 -help - display available options (--help-hidden for more)
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]845</pre></div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]846
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]847<p>... and the resultant program could be used just like the standard
848<tt>grep</tt> tool.</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]849
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]850<p>Positional arguments are sorted by their order of construction. This means
851that command line options will be ordered according to how they are listed in a
Reid Spencer2c8ab582004-08-13 20:19:14 +0000[diff] [blame]852.cpp file, but will not have an ordering defined if the positional arguments
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]853are defined in multiple .cpp files. The fix for this problem is simply to
854define all of your positional arguments in one .cpp file.</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]855
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]856</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]857
858
859<!-- _______________________________________________________________________ -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]860<div class="doc_subsubsection">
861 <a name="--">Specifying positional options with hyphens</a>
862</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]863
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]864<div class="doc_text">
865
866<p>Sometimes you may want to specify a value to your positional argument that
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]867starts with a hyphen (for example, searching for '<tt>-foo</tt>' in a file). At
868first, you will have trouble doing this, because it will try to find an argument
869named '<tt>-foo</tt>', and will fail (and single quotes will not save you).
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]870Note that the system <tt>grep</tt> has the same problem:</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]871
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]872<div class="doc_code"><pre>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]873 $ spiffygrep '-foo' test.txt
874 Unknown command line argument '-foo'. Try: spiffygrep --help'
875
876 $ grep '-foo' test.txt
877 grep: illegal option -- f
878 grep: illegal option -- o
879 grep: illegal option -- o
880 Usage: grep -hblcnsviw pattern file . . .
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]881</pre></div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]882
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]883<p>The solution for this problem is the same for both your tool and the system
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]884version: use the '<tt>--</tt>' marker. When the user specifies '<tt>--</tt>' on
885the command line, it is telling the program that all options after the
886'<tt>--</tt>' should be treated as positional arguments, not options. Thus, we
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]887can use it like this:</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]888
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]889<div class="doc_code"><pre>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]890 $ spiffygrep -- -foo test.txt
891 ...output...
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]892</pre></div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]893
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]894</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]895
896<!-- _______________________________________________________________________ -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]897<div class="doc_subsubsection">
Reid Spencer2c8ab582004-08-13 20:19:14 +0000[diff] [blame]898 <a name="getPosition">Determining absolute position with getPosition()</a>
899</div>
900<div class="doc_text">
901 <p>Sometimes an option can affect or modify the meaning of another option. For
902 example, consider <tt>gcc</tt>'s <tt>-x LANG</tt> option. This tells
903 <tt>gcc</tt> to ignore the suffix of subsequent positional arguments and force
904 the file to be interpreted as if it contained source code in language
905 <tt>LANG</tt>. In order to handle this properly , you need to know the
906 absolute position of each argument, especially those in lists, so their
907 interaction(s) can be applied correctly. This is also useful for options like
908 <tt>-llibname</tt> which is actually a positional argument that starts with
909 a dash.</p>
910 <p>So, generally, the problem is that you have two <tt>cl::list</tt> variables
911 that interact in some way. To ensure the correct interaction, you can use the
912 <tt>cl::list::getPosition(optnum)</tt> method. This method returns the
913 absolute position (as found on the command line) of the <tt>optnum</tt>
914 item in the <tt>cl::list</tt>.</p>
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]915 <p>The idiom for usage is like this:</p>
916
917 <div class="doc_code"><pre>
Reid Spencer2c8ab582004-08-13 20:19:14 +0000[diff] [blame]918 static cl::list&lt;std::string&gt; Files(cl::Positional, cl::OneOrMore);
919 static cl::listlt;std::string&gt; Libraries("l", cl::ZeroOrMore);
920
921 int main(int argc, char**argv) {
922 // ...
923 std::vector&lt;std::string&gt;::iterator fileIt = Files.begin();
924 std::vector&lt;std::string&gt;::iterator libIt = Libraries.begin();
925 unsigned libPos = 0, filePos = 0;
926 while ( 1 ) {
927 if ( libIt != Libraries.end() )
928 libPos = Libraries.getPosition( libIt - Libraries.begin() );
929 else
930 libPos = 0;
931 if ( fileIt != Files.end() )
932 filePos = Files.getPosition( fileIt - Files.begin() );
933 else
934 filePos = 0;
935
936 if ( filePos != 0 &amp;&amp; (libPos == 0 || filePos &lt; libPos) ) {
937 // Source File Is next
938 ++fileIt;
939 }
940 else if ( libPos != 0 &amp;&amp; (filePos == 0 || libPos &lt; filePos) ) {
941 // Library is next
942 ++libIt;
943 }
944 else
945 break; // we're done with the list
946 }
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]947 }</pre></div>
948
Reid Spencer2c8ab582004-08-13 20:19:14 +0000[diff] [blame]949 <p>Note that, for compatibility reasons, the <tt>cl::opt</tt> also supports an
950 <tt>unsigned getPosition()</tt> option that will provide the absolute position
951 of that option. You can apply the same approach as above with a
952 <tt>cl::opt</tt> and a <tt>cl::list</tt> option as you can with two lists.</p>
953</div>
954
955<!-- _______________________________________________________________________ -->
956<div class="doc_subsubsection">
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]957 <a name="cl::ConsumeAfter">The <tt>cl::ConsumeAfter</tt> modifier</a>
958</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]959
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]960<div class="doc_text">
961
962<p>The <tt>cl::ConsumeAfter</tt> <a href="#formatting">formatting option</a> is
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]963used to construct programs that use "interpreter style" option processing. With
964this style of option processing, all arguments specified after the last
965positional argument are treated as special interpreter arguments that are not
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]966interpreted by the command line argument.</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]967
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]968<p>As a concrete example, lets say we are developing a replacement for the
969standard Unix Bourne shell (<tt>/bin/sh</tt>). To run <tt>/bin/sh</tt>, first
970you specify options to the shell itself (like <tt>-x</tt> which turns on trace
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]971output), then you specify the name of the script to run, then you specify
972arguments to the script. These arguments to the script are parsed by the bourne
973shell command line option processor, but are not interpreted as options to the
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]974shell itself. Using the CommandLine library, we would specify this as:</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]975
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]976<div class="doc_code"><pre>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]977<a href="#cl::opt">cl::opt</a>&lt;string&gt; Script(<a href="#cl::Positional">cl::Positional</a>, <a href="#cl::desc">cl::desc</a>("<i>&lt;input script&gt;</i>"), <a href="#cl::init">cl::init</a>("-"));
978<a href="#cl::list">cl::list</a>&lt;string&gt; Argv(<a href="#cl::ConsumeAfter">cl::ConsumeAfter</a>, <a href="#cl::desc">cl::desc</a>("<i>&lt;program arguments&gt;...</i>"));
979<a href="#cl::opt">cl::opt</a>&lt;bool&gt; Trace("<i>x</i>", <a href="#cl::desc">cl::desc</a>("<i>Enable trace output</i>"));
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]980</pre></div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]981
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]982<p>which automatically provides the help output:</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]983
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]984<div class="doc_code"><pre>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]985USAGE: spiffysh [options] <b>&lt;input script&gt; &lt;program arguments&gt;...</b>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]986
987OPTIONS:
988 -help - display available options (--help-hidden for more)
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]989 <b>-x - Enable trace output</b>
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]990</pre></div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]991
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]992<p>At runtime, if we run our new shell replacement as `<tt>spiffysh -x test.sh
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]993-a -x -y bar</tt>', the <tt>Trace</tt> variable will be set to true, the
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]994<tt>Script</tt> variable will be set to "<tt>test.sh</tt>", and the
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]995<tt>Argv</tt> list will contain <tt>["-a", "-x", "-y", "bar"]</tt>, because they
996were specified after the last positional argument (which is the script
997name).</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]998
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]999<p>There are several limitations to when <tt>cl::ConsumeAfter</tt> options can
1000be specified. For example, only one <tt>cl::ConsumeAfter</tt> can be specified
1001per program, there must be at least one <a href="#positional">positional
Chris Lattnerbe801bf2004-05-06 22:03:59 +0000[diff] [blame]1002argument</a> specified, there must not be any <a href="#cl::list">cl::list</a>
1003positional arguments, and the <tt>cl::ConsumeAfter</tt> option should be a <a
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1004href="#cl::list">cl::list</a> option.</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1005
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1006</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1007
1008<!-- ======================================================================= -->
Chris Lattnerbe801bf2004-05-06 22:03:59 +0000[diff] [blame]1009<div class="doc_subsection">
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1010 <a name="storage">Internal vs External Storage</a>
1011</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1012
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1013<div class="doc_text">
1014
1015<p>By default, all command line options automatically hold the value that they
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1016parse from the command line. This is very convenient in the common case,
1017especially when combined with the ability to define command line options in the
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1018files that use them. This is called the internal storage model.</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1019
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1020<p>Sometimes, however, it is nice to separate the command line option processing
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1021code from the storage of the value parsed. For example, lets say that we have a
1022'<tt>-debug</tt>' option that we would like to use to enable debug information
1023across the entire body of our program. In this case, the boolean value
1024controlling the debug code should be globally accessable (in a header file, for
1025example) yet the command line option processing code should not be exposed to
1026all of these clients (requiring lots of .cpp files to #include
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1027<tt>CommandLine.h</tt>).</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1028
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1029<p>To do this, set up your .h file with your option, like this for example:</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1030
Misha Brukman1fc9f8e2005-02-09 22:49:05 +0000[diff] [blame]1031<div class="doc_code">
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1032<pre>
1033<i>// DebugFlag.h - Get access to the '-debug' command line option
1034//
1035
1036// DebugFlag - This boolean is set to true if the '-debug' command line option
1037// is specified. This should probably not be referenced directly, instead, use
1038// the DEBUG macro below.
1039//</i>
1040extern bool DebugFlag;
1041
1042<i>// DEBUG macro - This macro should be used by code to emit debug information.
1043// In the '-debug' option is specified on the command line, and if this is a
1044// debug build, then the code specified as the option to the macro will be
1045// executed. Otherwise it will not be. Example:
1046//
Bill Wendling832171c2006-12-07 20:04:42 +0000[diff] [blame]1047// DOUT &lt;&lt; "Bitset contains: " &lt;&lt; Bitset &lt;&lt; "\n";
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1048//</i>
Misha Brukman1fc9f8e2005-02-09 22:49:05 +0000[diff] [blame]1049<span class="doc_hilite">#ifdef NDEBUG
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1050#define DEBUG(X)
1051#else
Misha Brukman1fc9f8e2005-02-09 22:49:05 +0000[diff] [blame]1052#define DEBUG(X)</span> do { if (DebugFlag) { X; } } while (0)
1053<span class="doc_hilite">#endif</span>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1054</pre>
Misha Brukman1fc9f8e2005-02-09 22:49:05 +0000[diff] [blame]1055</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1056
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1057<p>This allows clients to blissfully use the <tt>DEBUG()</tt> macro, or the
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1058<tt>DebugFlag</tt> explicitly if they want to. Now we just need to be able to
1059set the <tt>DebugFlag</tt> boolean when the option is set. To do this, we pass
1060an additial argument to our command line argument processor, and we specify
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1061where to fill in with the <a href="#cl::location">cl::location</a>
1062attribute:</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1063
Misha Brukman1fc9f8e2005-02-09 22:49:05 +0000[diff] [blame]1064<div class="doc_code">
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1065<pre>
Misha Brukman1fc9f8e2005-02-09 22:49:05 +0000[diff] [blame]1066bool DebugFlag; <i>// the actual value</i>
Chris Lattner589a4cc2003-08-01 21:30:37 +0000[diff] [blame]1067static <a href="#cl::opt">cl::opt</a>&lt;bool, true&gt; <i>// The parser</i>
Misha Brukman1fc9f8e2005-02-09 22:49:05 +0000[diff] [blame]1068Debug("<i>debug</i>", <a href="#cl::desc">cl::desc</a>("<i>Enable debug output</i>"), <a href="#cl::Hidden">cl::Hidden</a>, <a href="#cl::location">cl::location</a>(DebugFlag));
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1069</pre>
Misha Brukman1fc9f8e2005-02-09 22:49:05 +0000[diff] [blame]1070</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1071
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1072<p>In the above example, we specify "<tt>true</tt>" as the second argument to
Misha Brukman1fc9f8e2005-02-09 22:49:05 +0000[diff] [blame]1073the <tt><a href="#cl::opt">cl::opt</a></tt> template, indicating that the
1074template should not maintain a copy of the value itself. In addition to this,
1075we specify the <tt><a href="#cl::location">cl::location</a></tt> attribute, so
1076that <tt>DebugFlag</tt> is automatically set.</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1077
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1078</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1079
1080<!-- ======================================================================= -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1081<div class="doc_subsection">
1082 <a name="attributes">Option Attributes</a>
1083</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1084
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1085<div class="doc_text">
1086
1087<p>This section describes the basic attributes that you can specify on
1088options.</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1089
1090<ul>
1091
1092<li>The option name attribute (which is required for all options, except <a
1093href="#positional">positional options</a>) specifies what the option name is.
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1094This option is specified in simple double quotes:
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1095
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1096<pre>
1097<a href="#cl::opt">cl::opt</a>&lt;<b>bool</b>&gt; Quiet("<i>quiet</i>");
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1098</pre>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1099
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1100</li>
1101
1102<li><a name="cl::desc">The <b><tt>cl::desc</tt></b></a> attribute specifies a
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1103description for the option to be shown in the <tt>--help</tt> output for the
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1104program.</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1105
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1106<li><a name="cl::value_desc">The <b><tt>cl::value_desc</tt></b></a> attribute
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1107specifies a string that can be used to fine tune the <tt>--help</tt> output for
1108a command line option. Look <a href="#value_desc_example">here</a> for an
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1109example.</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1110
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1111<li><a name="cl::init">The <b><tt>cl::init</tt></b></a> attribute specifies an
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1112inital value for a <a href="#cl::opt">scalar</a> option. If this attribute is
1113not specified then the command line option value defaults to the value created
Brian Gaeke9d292ff2003-08-19 22:56:22 +0000[diff] [blame]1114by the default constructor for the type. <b>Warning</b>: If you specify both
1115<b><tt>cl::init</tt></b> and <b><tt>cl::location</tt></b> for an option,
1116you must specify <b><tt>cl::location</tt></b> first, so that when the
1117command-line parser sees <b><tt>cl::init</tt></b>, it knows where to put the
1118initial value. (You will get an error at runtime if you don't put them in
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1119the right order.)</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1120
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1121<li><a name="cl::location">The <b><tt>cl::location</tt></b></a> attribute where to
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1122store the value for a parsed command line option if using external storage. See
1123the section on <a href="#storage">Internal vs External Storage</a> for more
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1124information.</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1125
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1126<li><a name="cl::aliasopt">The <b><tt>cl::aliasopt</tt></b></a> attribute
Misha Brukman1fc9f8e2005-02-09 22:49:05 +0000[diff] [blame]1127specifies which option a <tt><a href="#cl::alias">cl::alias</a></tt> option is
1128an alias for.</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1129
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1130<li><a name="cl::values">The <b><tt>cl::values</tt></b></a> attribute specifies
1131the string-to-value mapping to be used by the generic parser. It takes a
Chris Lattnerb406ead2004-07-16 00:10:54 +0000[diff] [blame]1132<b>clEnumValEnd terminated</b> list of (option, value, description) triplets
1133that
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1134specify the option name, the value mapped to, and the description shown in the
1135<tt>--help</tt> for the tool. Because the generic parser is used most
1136frequently with enum values, two macros are often useful:
1137
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1138<ol>
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1139
1140<li><a name="clEnumVal">The <b><tt>clEnumVal</tt></b></a> macro is used as a
1141nice simple way to specify a triplet for an enum. This macro automatically
1142makes the option name be the same as the enum name. The first option to the
1143macro is the enum, the second is the description for the command line
1144option.</li>
1145
1146<li><a name="clEnumValN">The <b><tt>clEnumValN</tt></b></a> macro is used to
1147specify macro options where the option name doesn't equal the enum name. For
1148this macro, the first argument is the enum value, the second is the flag name,
1149and the second is the description.</li>
1150
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1151</ol>
1152
1153You will get a compile time error if you try to use cl::values with a parser
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1154that does not support it.</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1155
1156</ul>
1157
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1158</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1159
1160<!-- ======================================================================= -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1161<div class="doc_subsection">
1162 <a name="modifiers">Option Modifiers</a>
1163</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1164
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1165<div class="doc_text">
1166
1167<p>Option modifiers are the flags and expressions that you pass into the
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1168constructors for <tt><a href="#cl::opt">cl::opt</a></tt> and <tt><a
1169href="#cl::list">cl::list</a></tt>. These modifiers give you the ability to
1170tweak how options are parsed and how <tt>--help</tt> output is generated to fit
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1171your application well.</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1172
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1173<p>These options fall into five main catagories:</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1174
1175<ol>
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1176<li><a href="#hiding">Hiding an option from <tt>--help</tt> output</a></li>
1177<li><a href="#numoccurrences">Controlling the number of occurrences
1178 required and allowed</a></li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1179<li><a href="#valrequired">Controlling whether or not a value must be
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1180 specified</a></li>
1181<li><a href="#formatting">Controlling other formatting options</a></li>
1182<li><a href="#misc">Miscellaneous option modifiers</a></li>
1183</ol>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1184
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1185<p>It is not possible to specify two options from the same catagory (you'll get
1186a runtime error) to a single option, except for options in the miscellaneous
Chris Lattner32a32842003-05-22 20:36:06 +0000[diff] [blame]1187catagory. The CommandLine library specifies defaults for all of these settings
1188that are the most useful in practice and the most common, which mean that you
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1189usually shouldn't have to worry about these.</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1190
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1191</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1192
1193<!-- _______________________________________________________________________ -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1194<div class="doc_subsubsection">
1195 <a name="hiding">Hiding an option from <tt>--help</tt> output</a>
1196</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1197
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1198<div class="doc_text">
1199
1200<p>The <tt>cl::NotHidden</tt>, <tt>cl::Hidden</tt>, and
1201<tt>cl::ReallyHidden</tt> modifiers are used to control whether or not an option
1202appears in the <tt>--help</tt> and <tt>--help-hidden</tt> output for the
1203compiled program:</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1204
1205<ul>
1206
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1207<li><a name="cl::NotHidden">The <b><tt>cl::NotHidden</tt></b></a> modifier
1208(which is the default for <tt><a href="#cl::opt">cl::opt</a></tt> and <tt><a
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1209href="#cl::list">cl::list</a></tt> options), indicates the option is to appear
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1210in both help listings.</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1211
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1212<li><a name="cl::Hidden">The <b><tt>cl::Hidden</tt></b></a> modifier (which is the
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1213default for <tt><a href="#cl::alias">cl::alias</a></tt> options), indicates that
1214the option should not appear in the <tt>--help</tt> output, but should appear in
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1215the <tt>--help-hidden</tt> output.</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1216
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1217<li><a name="cl::ReallyHidden">The <b><tt>cl::ReallyHidden</tt></b></a> modifier,
1218indicates that the option should not appear in any help output.</li>
1219
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1220</ul>
1221
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1222</div>
1223
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1224<!-- _______________________________________________________________________ -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1225<div class="doc_subsubsection">
1226 <a name="numoccurrences">Controlling the number of occurrences required and
1227 allowed</a>
1228</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1229
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1230<div class="doc_text">
1231
1232<p>This group of options is used to control how many time an option is allowed
1233(or required) to be specified on the command line of your program. Specifying a
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1234value for this setting allows the CommandLine library to do error checking for
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1235you.</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1236
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1237<p>The allowed values for this option group are:</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1238
1239<ul>
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1240
1241<li><a name="cl::Optional">The <b><tt>cl::Optional</tt></b></a> modifier (which
1242is the default for the <tt><a href="#cl::opt">cl::opt</a></tt> and <tt><a
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1243href="#cl::alias">cl::alias</a></tt> classes) indicates that your program will
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1244allow either zero or one occurrence of the option to be specified.</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1245
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1246<li><a name="cl::ZeroOrMore">The <b><tt>cl::ZeroOrMore</tt></b></a> modifier
1247(which is the default for the <tt><a href="#cl::list">cl::list</a></tt> class)
1248indicates that your program will allow the option to be specified zero or more
1249times.</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1250
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1251<li><a name="cl::Required">The <b><tt>cl::Required</tt></b></a> modifier
1252indicates that the specified option must be specified exactly one time.</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1253
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1254<li><a name="cl::OneOrMore">The <b><tt>cl::OneOrMore</tt></b></a> modifier
1255indicates that the option must be specified at least one time.</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1256
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1257<li>The <b><tt>cl::ConsumeAfter</tt></b> modifier is described in the <a
1258href="#positional">Positional arguments section</a></li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1259
1260</ul>
1261
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1262<p>If an option is not specified, then the value of the option is equal to the
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1263value specified by the <tt><a href="#cl::init">cl::init</a></tt> attribute. If
1264the <tt><a href="#cl::init">cl::init</a></tt> attribute is not specified, the
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1265option value is initialized with the default constructor for the data type.</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1266
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1267<p>If an option is specified multiple times for an option of the <tt><a
1268href="#cl::opt">cl::opt</a></tt> class, only the last value will be
1269retained.</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1270
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1271</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1272
1273<!-- _______________________________________________________________________ -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1274<div class="doc_subsubsection">
1275 <a name="valrequired">Controlling whether or not a value must be specified</a>
1276</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1277
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1278<div class="doc_text">
1279
1280<p>This group of options is used to control whether or not the option allows a
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1281value to be present. In the case of the CommandLine library, a value is either
1282specified with an equal sign (e.g. '<tt>-index-depth=17</tt>') or as a trailing
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1283string (e.g. '<tt>-o a.out</tt>').</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1284
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1285<p>The allowed values for this option group are:</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1286
1287<ul>
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1288
1289<li><a name="cl::ValueOptional">The <b><tt>cl::ValueOptional</tt></b></a> modifier
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1290(which is the default for <tt>bool</tt> typed options) specifies that it is
1291acceptable to have a value, or not. A boolean argument can be enabled just by
1292appearing on the command line, or it can have an explicit '<tt>-foo=true</tt>'.
1293If an option is specified with this mode, it is illegal for the value to be
1294provided without the equal sign. Therefore '<tt>-foo true</tt>' is illegal. To
1295get this behavior, you must use the <a
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1296href="#cl::ValueRequired">cl::ValueRequired</a> modifier.</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1297
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1298<li><a name="cl::ValueRequired">The <b><tt>cl::ValueRequired</tt></b></a> modifier
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1299(which is the default for all other types except for <a
1300href="#onealternative">unnamed alternatives using the generic parser</a>)
1301specifies that a value must be provided. This mode informs the command line
1302library that if an option is not provides with an equal sign, that the next
1303argument provided must be the value. This allows things like '<tt>-o
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1304a.out</tt>' to work.</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1305
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1306<li><a name="cl::ValueDisallowed">The <b><tt>cl::ValueDisallowed</tt></b></a>
1307modifier (which is the default for <a href="#onealternative">unnamed
1308alternatives using the generic parser</a>) indicates that it is a runtime error
1309for the user to specify a value. This can be provided to disallow users from
1310providing options to boolean options (like '<tt>-foo=true</tt>').</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1311
1312</ul>
1313
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1314<p>In general, the default values for this option group work just like you would
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1315want them to. As mentioned above, you can specify the <a
1316href="#cl::ValueDisallowed">cl::ValueDisallowed</a> modifier to a boolean
1317argument to restrict your command line parser. These options are mostly useful
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1318when <a href="#extensionguide">extending the library</a>.</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1319
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1320</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1321
1322<!-- _______________________________________________________________________ -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1323<div class="doc_subsubsection">
1324 <a name="formatting">Controlling other formatting options</a>
1325</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1326
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1327<div class="doc_text">
1328
1329<p>The formatting option group is used to specify that the command line option
1330has special abilities and is otherwise different from other command line
1331arguments. As usual, you can only specify at most one of these arguments.</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1332
1333<ul>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1334
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1335<li><a name="cl::NormalFormatting">The <b><tt>cl::NormalFormatting</tt></b></a>
1336modifier (which is the default all options) specifies that this option is
1337"normal".</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1338
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1339<li><a name="cl::Positional">The <b><tt>cl::Positional</tt></b></a> modifier
1340specifies that this is a positional argument, that does not have a command line
1341option associated with it. See the <a href="#positional">Positional
1342Arguments</a> section for more information.</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1343
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1344<li>The <b><a href="#cl::ConsumeAfter"><tt>cl::ConsumeAfter</tt></a></b> modifier
1345specifies that this option is used to capture "interpreter style" arguments. See <a href="#cl::ConsumeAfter">this section for more information</a>.</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1346
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1347<li><a name="cl::Prefix">The <b><tt>cl::Prefix</tt></b></a> modifier specifies
Reid Spencer5f8448f2004-11-24 06:13:42 +0000[diff] [blame]1348that this option prefixes its value. With 'Prefix' options, the equal sign does
1349not separate the value from the option name specified. Instead, the value is
1350everything after the prefix, including any equal sign if present. This is useful
1351for processing odd arguments like <tt>-lmalloc</tt> and <tt>-L/usr/lib</tt> in a
Misha Brukmanc43d9142005-05-10 22:05:27 +0000[diff] [blame]1352linker tool or <tt>-DNAME=value</tt> in a compiler tool. Here, the
Reid Spencer5f8448f2004-11-24 06:13:42 +0000[diff] [blame]1353'<tt>l</tt>', '<tt>D</tt>' and '<tt>L</tt>' options are normal string (or list)
Misha Brukmanc43d9142005-05-10 22:05:27 +0000[diff] [blame]1354options, that have the <b><tt><a href="#cl::Prefix">cl::Prefix</a></tt></b>
1355modifier added to allow the CommandLine library to recognize them. Note that
1356<b><tt><a href="#cl::Prefix">cl::Prefix</a></tt></b> options must not have the
1357<b><tt><a href="#cl::ValueDisallowed">cl::ValueDisallowed</a></tt></b> modifier
1358specified.</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1359
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1360<li><a name="cl::Grouping">The <b><tt>cl::Grouping</tt></b></a> modifier is used
1361to implement unix style tools (like <tt>ls</tt>) that have lots of single letter
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1362arguments, but only require a single dash. For example, the '<tt>ls -labF</tt>'
1363command actually enables four different options, all of which are single
Misha Brukmanc43d9142005-05-10 22:05:27 +0000[diff] [blame]1364letters. Note that <b><tt><a href="#cl::Grouping">cl::Grouping</a></tt></b>
1365options cannot have values.</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1366
1367</ul>
1368
Misha Brukmanc43d9142005-05-10 22:05:27 +0000[diff] [blame]1369<p>The CommandLine library does not restrict how you use the <b><tt><a
1370href="#cl::Prefix">cl::Prefix</a></tt></b> or <b><tt><a
1371href="#cl::Grouping">cl::Grouping</a></tt></b> modifiers, but it is possible to
1372specify ambiguous argument settings. Thus, it is possible to have multiple
1373letter options that are prefix or grouping options, and they will still work as
1374designed.</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1375
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1376<p>To do this, the CommandLine library uses a greedy algorithm to parse the
1377input option into (potentially multiple) prefix and grouping options. The
1378strategy basically looks like this:</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1379
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]1380<div class="doc_code"><tt>parse(string OrigInput) {</tt>
Misha Brukmanc53aefb2004-05-12 18:42:35 +0000[diff] [blame]1381
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1382<ol>
1383<li><tt>string input = OrigInput;</tt>
1384<li><tt>if (isOption(input)) return getOption(input).parse();</tt>&nbsp;&nbsp;&nbsp;&nbsp;<i>// Normal option</i>
1385<li><tt>while (!isOption(input) &amp;&amp; !input.empty()) input.pop_back();</tt>&nbsp;&nbsp;&nbsp;&nbsp;<i>// Remove the last letter</i>
1386<li><tt>if (input.empty()) return error();</tt>&nbsp;&nbsp;&nbsp;&nbsp;<i>// No matching option</i>
1387<li><tt>if (getOption(input).isPrefix())<br>
1388&nbsp;&nbsp;return getOption(input).parse(input);</tt>
1389<li><tt>while (!input.empty()) {&nbsp;&nbsp;&nbsp;&nbsp;<i>// Must be grouping options</i><br>
1390&nbsp;&nbsp;getOption(input).parse();<br>
1391&nbsp;&nbsp;OrigInput.erase(OrigInput.begin(), OrigInput.begin()+input.length());<br>
1392&nbsp;&nbsp;input = OrigInput;<br>
1393&nbsp;&nbsp;while (!isOption(input) &amp;&amp; !input.empty()) input.pop_back();<br>
1394}</tt>
Misha Brukmanc53aefb2004-05-12 18:42:35 +0000[diff] [blame]1395<li><tt>if (!OrigInput.empty()) error();</tt></li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1396</ol>
Misha Brukmanc53aefb2004-05-12 18:42:35 +0000[diff] [blame]1397
1398<p><tt>}</tt></p>
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]1399</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1400
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1401</div>
Chris Lattner32a32842003-05-22 20:36:06 +0000[diff] [blame]1402
1403<!-- _______________________________________________________________________ -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1404<div class="doc_subsubsection">
1405 <a name="misc">Miscellaneous option modifiers</a>
1406</div>
Chris Lattner32a32842003-05-22 20:36:06 +0000[diff] [blame]1407
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1408<div class="doc_text">
1409
1410<p>The miscellaneous option modifiers are the only flags where you can specify
1411more than one flag from the set: they are not mutually exclusive. These flags
1412specify boolean properties that modify the option.</p>
Chris Lattner32a32842003-05-22 20:36:06 +0000[diff] [blame]1413
1414<ul>
1415
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1416<li><a name="cl::CommaSeparated">The <b><tt>cl::CommaSeparated</tt></b></a> modifier
Chris Lattner32a32842003-05-22 20:36:06 +0000[diff] [blame]1417indicates that any commas specified for an option's value should be used to
1418split the value up into multiple values for the option. For example, these two
1419options are equivalent when <tt>cl::CommaSeparated</tt> is specified:
1420"<tt>-foo=a -foo=b -foo=c</tt>" and "<tt>-foo=a,b,c</tt>". This option only
1421makes sense to be used in a case where the option is allowed to accept one or
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1422more values (i.e. it is a <a href="#cl::list">cl::list</a> option).</li>
1423
Chris Lattnerbe801bf2004-05-06 22:03:59 +0000[diff] [blame]1424<li><a name="cl::PositionalEatsArgs">The
1425<b><tt>cl::PositionalEatsArgs</tt></b></a> modifier (which only applies to
1426positional arguments, and only makes sense for lists) indicates that positional
1427argument should consume any strings after it (including strings that start with
1428a "-") up until another recognized positional argument. For example, if you
1429have two "eating" positional arguments "<tt>pos1</tt>" and "<tt>pos2</tt>" the
1430string "<tt>-pos1 -foo -bar baz -pos2 -bork</tt>" would cause the "<tt>-foo -bar
1431-baz</tt>" strings to be applied to the "<tt>-pos1</tt>" option and the
1432"<tt>-bork</tt>" string to be applied to the "<tt>-pos2</tt>" option.</li>
1433
Chris Lattner32a32842003-05-22 20:36:06 +0000[diff] [blame]1434</ul>
1435
Chris Lattnerbe801bf2004-05-06 22:03:59 +0000[diff] [blame]1436<p>So far, these are the only two miscellaneous option modifiers.</p>
Chris Lattner32a32842003-05-22 20:36:06 +0000[diff] [blame]1437
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1438</div>
Chris Lattner32a32842003-05-22 20:36:06 +0000[diff] [blame]1439
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1440<!-- ======================================================================= -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1441<div class="doc_subsection">
1442 <a name="toplevel">Top-Level Classes and Functions</a>
1443</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1444
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1445<div class="doc_text">
1446
1447<p>Despite all of the built-in flexibility, the CommandLine option library
1448really only consists of one function (<a
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1449href="#cl::ParseCommandLineOptions"><tt>cl::ParseCommandLineOptions</tt></a>)
1450and three main classes: <a href="#cl::opt"><tt>cl::opt</tt></a>, <a
1451href="#cl::list"><tt>cl::list</tt></a>, and <a
1452href="#cl::alias"><tt>cl::alias</tt></a>. This section describes these three
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1453classes in detail.</p>
1454
1455</div>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1456
1457<!-- _______________________________________________________________________ -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1458<div class="doc_subsubsection">
1459 <a name="cl::ParseCommandLineOptions">The <tt>cl::ParseCommandLineOptions</tt>
1460 function</a>
1461</div>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1462
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1463<div class="doc_text">
1464
1465<p>The <tt>cl::ParseCommandLineOptions</tt> function is designed to be called
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1466directly from <tt>main</tt>, and is used to fill in the values of all of the
1467command line option variables once <tt>argc</tt> and <tt>argv</tt> are
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1468available.</p>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1469
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1470<p>The <tt>cl::ParseCommandLineOptions</tt> function requires two parameters
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1471(<tt>argc</tt> and <tt>argv</tt>), but may also take an optional third parameter
1472which holds <a href="#description">additional extra text</a> to emit when the
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1473<tt>--help</tt> option is invoked.</p>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1474
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1475</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1476
1477<!-- _______________________________________________________________________ -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1478<div class="doc_subsubsection">
1479 <a name="cl::ParseEnvironmentOptions">The <tt>cl::ParseEnvironmentOptions</tt>
1480 function</a>
1481</div>
Brian Gaekee5842852003-08-19 23:11:43 +0000[diff] [blame]1482
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1483<div class="doc_text">
Brian Gaekee5842852003-08-19 23:11:43 +0000[diff] [blame]1484
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1485<p>The <tt>cl::ParseEnvironmentOptions</tt> function has mostly the same effects
1486as <a
1487href="#cl::ParseCommandLineOptions"><tt>cl::ParseCommandLineOptions</tt></a>,
1488except that it is designed to take values for options from an environment
1489variable, for those cases in which reading the command line is not convenient or
1490not desired. It fills in the values of all the command line option variables
1491just like <a
1492href="#cl::ParseCommandLineOptions"><tt>cl::ParseCommandLineOptions</tt></a>
1493does.</p>
1494
1495<p>It takes three parameters: first, the name of the program (since
1496<tt>argv</tt> may not be available, it can't just look in <tt>argv[0]</tt>),
1497second, the name of the environment variable to examine, and third, the optional
Brian Gaekee5842852003-08-19 23:11:43 +0000[diff] [blame]1498<a href="#description">additional extra text</a> to emit when the
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1499<tt>--help</tt> option is invoked.</p>
Brian Gaekee5842852003-08-19 23:11:43 +0000[diff] [blame]1500
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1501<p><tt>cl::ParseEnvironmentOptions</tt> will break the environment
Brian Gaekee5842852003-08-19 23:11:43 +0000[diff] [blame]1502variable's value up into words and then process them using
1503<a href="#cl::ParseCommandLineOptions"><tt>cl::ParseCommandLineOptions</tt></a>.
1504<b>Note:</b> Currently <tt>cl::ParseEnvironmentOptions</tt> does not support
1505quoting, so an environment variable containing <tt>-option "foo bar"</tt> will
1506be parsed as three words, <tt>-option</tt>, <tt>"foo</tt>, and <tt>bar"</tt>,
1507which is different from what you would get from the shell with the same
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1508input.</p>
1509
1510</div>
Brian Gaekee5842852003-08-19 23:11:43 +0000[diff] [blame]1511
1512<!-- _______________________________________________________________________ -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1513<div class="doc_subsubsection">
Reid Spencer2403b852006-06-05 17:30:16 +0000[diff] [blame]1514 <a name="cl::SetVersionPrinter">The <tt>cl::SetVersionPrinter</tt>
1515 function</a>
1516</div>
1517
1518<div class="doc_text">
1519
1520<p>The <tt>cl::SetVersionPrinter</tt> function is designed to be called
1521directly from <tt>main</tt>, and <i>before</i>
1522<tt>cl::ParseCommandLineOptions</tt>. Its use is optional. It simply arranges
1523for a function to be called in response to the <tt>--version</tt> option instead
1524of having the <tt>CommandLine</tt> library print out the usual version string
1525for LLVM. This is useful for programs that are not part of LLVM but wish to use
1526the <tt>CommandLine</tt> facilities. Such programs should just define a small
1527function that takes no arguments and returns <tt>void</tt> and that prints out
1528whatever version information is appropriate for the program. Pass the address
1529of that function to <tt>cl::SetVersionPrinter</tt> to arrange for it to be
1530called when the <tt>--version</tt> option is given by the user.</p>
1531
1532</div>
1533<!-- _______________________________________________________________________ -->
1534<div class="doc_subsubsection">
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1535 <a name="cl::opt">The <tt>cl::opt</tt> class</a>
1536</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1537
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1538<div class="doc_text">
1539
1540<p>The <tt>cl::opt</tt> class is the class used to represent scalar command line
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1541options, and is the one used most of the time. It is a templated class which
1542can take up to three arguments (all except for the first have default values
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1543though):</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1544
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]1545<div class="doc_code"><pre>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1546<b>namespace</b> cl {
1547 <b>template</b> &lt;<b>class</b> DataType, <b>bool</b> ExternalStorage = <b>false</b>,
1548 <b>class</b> ParserClass = parser&lt;DataType&gt; &gt;
1549 <b>class</b> opt;
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1550}
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]1551</pre></div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1552
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1553<p>The first template argument specifies what underlying data type the command
1554line argument is, and is used to select a default parser implementation. The
1555second template argument is used to specify whether the option should contain
1556the storage for the option (the default) or whether external storage should be
1557used to contain the value parsed for the option (see <a href="#storage">Internal
1558vs External Storage</a> for more information).</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1559
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1560<p>The third template argument specifies which parser to use. The default value
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1561selects an instantiation of the <tt>parser</tt> class based on the underlying
1562data type of the option. In general, this default works well for most
1563applications, so this option is only used when using a <a
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1564href="#customparser">custom parser</a>.</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1565
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1566</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1567
1568<!-- _______________________________________________________________________ -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1569<div class="doc_subsubsection">
1570 <a name="cl::list">The <tt>cl::list</tt> class</a>
1571</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1572
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1573<div class="doc_text">
1574
1575<p>The <tt>cl::list</tt> class is the class used to represent a list of command
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1576line options. It too is a templated class which can take up to three
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1577arguments:</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1578
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]1579<div class="doc_code"><pre>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1580<b>namespace</b> cl {
1581 <b>template</b> &lt;<b>class</b> DataType, <b>class</b> Storage = <b>bool</b>,
1582 <b>class</b> ParserClass = parser&lt;DataType&gt; &gt;
1583 <b>class</b> list;
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1584}
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]1585</pre></div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1586
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1587<p>This class works the exact same as the <a
1588href="#cl::opt"><tt>cl::opt</tt></a> class, except that the second argument is
1589the <b>type</b> of the external storage, not a boolean value. For this class,
1590the marker type '<tt>bool</tt>' is used to indicate that internal storage should
1591be used.</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1592
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1593</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1594
1595<!-- _______________________________________________________________________ -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1596<div class="doc_subsubsection">
Jim Laskey1d8f6262005-08-25 22:52:43 +0000[diff] [blame]1597 <a name="cl::bits">The <tt>cl::bits</tt> class</a>
1598</div>
1599
1600<div class="doc_text">
1601
1602<p>The <tt>cl::bits</tt> class is the class used to represent a list of command
1603line options in the form of a bit vector. It is also a templated class which
1604can take up to three arguments:</p>
1605
1606<div class="doc_code"><pre>
1607<b>namespace</b> cl {
1608 <b>template</b> &lt;<b>class</b> DataType, <b>class</b> Storage = <b>bool</b>,
1609 <b>class</b> ParserClass = parser&lt;DataType&gt; &gt;
1610 <b>class</b> bits;
1611}
1612</pre></div>
1613
1614<p>This class works the exact same as the <a
1615href="#cl::opt"><tt>cl::lists</tt></a> class, except that the second argument
Jim Laskey22b7dfa2005-08-26 09:25:54 +0000[diff] [blame]1616must be of <b>type</b> <tt>unsigned</tt> if external storage is used.</p>
Jim Laskey1d8f6262005-08-25 22:52:43 +0000[diff] [blame]1617
1618</div>
1619
1620<!-- _______________________________________________________________________ -->
1621<div class="doc_subsubsection">
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1622 <a name="cl::alias">The <tt>cl::alias</tt> class</a>
1623</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1624
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1625<div class="doc_text">
1626
1627<p>The <tt>cl::alias</tt> class is a nontemplated class that is used to form
1628aliases for other arguments.</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1629
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]1630<div class="doc_code"><pre>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1631<b>namespace</b> cl {
1632 <b>class</b> alias;
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1633}
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]1634</pre></div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1635
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1636<p>The <a href="#cl::aliasopt"><tt>cl::aliasopt</tt></a> attribute should be
1637used to specify which option this is an alias for. Alias arguments default to
1638being <a href="#cl::Hidden">Hidden</a>, and use the aliased options parser to do
1639the conversion from string to data.</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1640
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1641</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1642
Reid Spencer9bbba0912004-11-16 06:11:52 +0000[diff] [blame]1643<!-- _______________________________________________________________________ -->
1644<div class="doc_subsubsection">
1645 <a name="cl::extrahelp">The <tt>cl::extrahelp</tt> class</a>
1646</div>
1647
1648<div class="doc_text">
1649
1650<p>The <tt>cl::extrahelp</tt> class is a nontemplated class that allows extra
1651help text to be printed out for the <tt>--help</tt> option.</p>
1652
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]1653<div class="doc_code"><pre>
Reid Spencer9bbba0912004-11-16 06:11:52 +0000[diff] [blame]1654<b>namespace</b> cl {
1655 <b>struct</b> extrahelp;
1656}
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]1657</pre></div>
Reid Spencer9bbba0912004-11-16 06:11:52 +0000[diff] [blame]1658
1659<p>To use the extrahelp, simply construct one with a <tt>const char*</tt>
1660parameter to the constructor. The text passed to the constructor will be printed
1661at the bottom of the help message, verbatim. Note that multiple
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]1662<tt>cl::extrahelp</tt> <b>can</b> be used, but this practice is discouraged. If
Reid Spencer9bbba0912004-11-16 06:11:52 +0000[diff] [blame]1663your tool needs to print additional help information, put all that help into a
1664single <tt>cl::extrahelp</tt> instance.</p>
1665<p>For example:</p>
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]1666<div class="doc_code"><pre>
Reid Spencer9bbba0912004-11-16 06:11:52 +0000[diff] [blame]1667 cl::extrahelp("\nADDITIONAL HELP:\n\n This is the extra help\n");
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]1668</pre></div>
Reid Spencer9bbba0912004-11-16 06:11:52 +0000[diff] [blame]1669</div>
1670
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1671<!-- ======================================================================= -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1672<div class="doc_subsection">
1673 <a name="builtinparsers">Builtin parsers</a>
1674</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1675
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1676<div class="doc_text">
1677
1678<p>Parsers control how the string value taken from the command line is
1679translated into a typed value, suitable for use in a C++ program. By default,
1680the CommandLine library uses an instance of <tt>parser&lt;type&gt;</tt> if the
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1681command line option specifies that it uses values of type '<tt>type</tt>'.
1682Because of this, custom option processing is specified with specializations of
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1683the '<tt>parser</tt>' class.</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1684
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1685<p>The CommandLine library provides the following builtin parser
1686specializations, which are sufficient for most applications. It can, however,
1687also be extended to work with new data types and new ways of interpreting the
1688same data. See the <a href="#customparser">Writing a Custom Parser</a> for more
1689details on this type of library extension.</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1690
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1691<ul>
1692
1693<li><a name="genericparser">The <b>generic <tt>parser&lt;t&gt;</tt> parser</b></a>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1694can be used to map strings values to any data type, through the use of the <a
1695href="#cl::values">cl::values</a> property, which specifies the mapping
1696information. The most common use of this parser is for parsing enum values,
1697which allows you to use the CommandLine library for all of the error checking to
1698make sure that only valid enum values are specified (as opposed to accepting
1699arbitrary strings). Despite this, however, the generic parser class can be used
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1700for any data type.</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1701
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1702<li><a name="boolparser">The <b><tt>parser&lt;bool&gt;</tt> specialization</b></a>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1703is used to convert boolean strings to a boolean value. Currently accepted
1704strings are "<tt>true</tt>", "<tt>TRUE</tt>", "<tt>True</tt>", "<tt>1</tt>",
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1705"<tt>false</tt>", "<tt>FALSE</tt>", "<tt>False</tt>", and "<tt>0</tt>".</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1706
Dale Johannesen0f2c8fc2007-05-22 18:32:34 +0000[diff] [blame^]1707<li><a name="boolOrDefaultparser">The <b><tt>parser&lt;boolOrDefault&gt;</tt>
1708 specialization</b></a> is used for cases where the value is boolean,
1709but we also need to know whether the option was specified at all. boolOrDefault
1710is an enum with 3 values, BOU_UNSET, BOU_TRUE and BOU_FALSE. This parser accepts
1711the same strings as <b><tt>parser&lt;bool&gt;</tt></b>.</li>
1712
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1713<li><a name="stringparser">The <b><tt>parser&lt;string&gt;</tt>
1714specialization</b></a> simply stores the parsed string into the string value
1715specified. No conversion or modification of the data is performed.</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1716
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1717<li><a name="intparser">The <b><tt>parser&lt;int&gt;</tt> specialization</b></a>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1718uses the C <tt>strtol</tt> function to parse the string input. As such, it will
1719accept a decimal number (with an optional '+' or '-' prefix) which must start
1720with a non-zero digit. It accepts octal numbers, which are identified with a
1721'<tt>0</tt>' prefix digit, and hexadecimal numbers with a prefix of
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1722'<tt>0x</tt>' or '<tt>0X</tt>'.</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1723
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1724<li><a name="doubleparser">The <b><tt>parser&lt;double&gt;</tt></b></a> and
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1725<b><tt>parser&lt;float&gt;</tt> specializations</b> use the standard C
1726<tt>strtod</tt> function to convert floating point strings into floating point
1727values. As such, a broad range of string formats is supported, including
1728exponential notation (ex: <tt>1.7e15</tt>) and properly supports locales.
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1729</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1730
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1731</ul>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]1732
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1733</div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]1734
1735<!-- *********************************************************************** -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1736<div class="doc_section">
1737 <a name="extensionguide">Extension Guide</a>
1738</div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]1739<!-- *********************************************************************** -->
1740
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1741<div class="doc_text">
1742
1743<p>Although the CommandLine library has a lot of functionality built into it
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1744already (as discussed previously), one of its true strengths lie in its
1745extensibility. This section discusses how the CommandLine library works under
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1746the covers and illustrates how to do some simple, common, extensions.</p>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1747
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1748</div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]1749
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1750<!-- ======================================================================= -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1751<div class="doc_subsection">
1752 <a name="customparser">Writing a custom parser</a>
1753</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1754
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1755<div class="doc_text">
1756
1757<p>One of the simplest and most common extensions is the use of a custom parser.
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1758As <a href="#builtinparsers">discussed previously</a>, parsers are the portion
1759of the CommandLine library that turns string input from the user into a
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1760particular parsed data type, validating the input in the process.</p>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1761
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1762<p>There are two ways to use a new parser:</p>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1763
1764<ol>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1765
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1766<li>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1767
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1768<p>Specialize the <a href="#genericparser"><tt>cl::parser</tt></a> template for
1769your custom data type.<p>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1770
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1771<p>This approach has the advantage that users of your custom data type will
1772automatically use your custom parser whenever they define an option with a value
1773type of your data type. The disadvantage of this approach is that it doesn't
Jim Laskeyf55914a2006-07-31 20:18:49 +0000[diff] [blame]1774work if your fundamental data type is something that is already supported.</p>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1775
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1776</li>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1777
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1778<li>
1779
1780<p>Write an independent class, using it explicitly from options that need
1781it.</p>
1782
1783<p>This approach works well in situations where you would line to parse an
1784option using special syntax for a not-very-special data-type. The drawback of
1785this approach is that users of your parser have to be aware that they are using
1786your parser, instead of the builtin ones.</p>
1787
1788</li>
1789
1790</ol>
1791
1792<p>To guide the discussion, we will discuss a custom parser that accepts file
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1793sizes, specified with an optional unit after the numeric size. For example, we
1794would like to parse "102kb", "41M", "1G" into the appropriate integer value. In
1795this case, the underlying data type we want to parse into is
1796'<tt>unsigned</tt>'. We choose approach #2 above because we don't want to make
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1797this the default for all <tt>unsigned</tt> options.</p>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1798
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1799<p>To start out, we declare our new <tt>FileSizeParser</tt> class:</p>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1800
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]1801<div class="doc_code"><pre>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1802<b>struct</b> FileSizeParser : <b>public</b> cl::basic_parser&lt;<b>unsigned</b>&gt; {
1803 <i>// parse - Return true on error.</i>
1804 <b>bool</b> parse(cl::Option &amp;O, <b>const char</b> *ArgName, <b>const</b> std::string &amp;ArgValue,
1805 <b>unsigned</b> &amp;Val);
1806};
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]1807</pre></div>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1808
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1809<p>Our new class inherits from the <tt>cl::basic_parser</tt> template class to
1810fill in the default, boiler plate, code for us. We give it the data type that
1811we parse into (the last argument to the <tt>parse</tt> method so that clients of
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1812our custom parser know what object type to pass in to the parse method (here we
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1813declare that we parse into '<tt>unsigned</tt>' variables.</p>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1814
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1815<p>For most purposes, the only method that must be implemented in a custom
1816parser is the <tt>parse</tt> method. The <tt>parse</tt> method is called
1817whenever the option is invoked, passing in the option itself, the option name,
1818the string to parse, and a reference to a return value. If the string to parse
1819is not well formed, the parser should output an error message and return true.
1820Otherwise it should return false and set '<tt>Val</tt>' to the parsed value. In
1821our example, we implement <tt>parse</tt> as:</p>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1822
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]1823<div class="doc_code"><pre>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1824<b>bool</b> FileSizeParser::parse(cl::Option &amp;O, <b>const char</b> *ArgName,
1825 <b>const</b> std::string &amp;Arg, <b>unsigned</b> &amp;Val) {
1826 <b>const char</b> *ArgStart = Arg.c_str();
1827 <b>char</b> *End;
1828
1829 <i>// Parse integer part, leaving 'End' pointing to the first non-integer char</i>
1830 Val = (unsigned)strtol(ArgStart, &amp;End, 0);
1831
1832 <b>while</b> (1) {
1833 <b>switch</b> (*End++) {
Chris Lattnerce5fcc32005-08-22 16:24:25 +0000[diff] [blame]1834 <b>case</b> 0: <b>return</b> false; <i>// No error</i>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1835 <b>case</b> 'i': <i>// Ignore the 'i' in KiB if people use that</i>
1836 <b>case</b> 'b': <b>case</b> 'B': <i>// Ignore B suffix</i>
1837 <b>break</b>;
1838
1839 <b>case</b> 'g': <b>case</b> 'G': Val *= 1024*1024*1024; <b>break</b>;
1840 <b>case</b> 'm': <b>case</b> 'M': Val *= 1024*1024; <b>break</b>;
1841 <b>case</b> 'k': <b>case</b> 'K': Val *= 1024; <b>break</b>;
1842
1843 default:
1844 <i>// Print an error message if unrecognized character!</i>
1845 <b>return</b> O.error(": '" + Arg + "' value invalid for file size argument!");
1846 }
1847 }
1848}
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]1849</pre></div>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1850
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1851<p>This function implements a very simple parser for the kinds of strings we are
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1852interested in. Although it has some holes (it allows "<tt>123KKK</tt>" for
1853example), it is good enough for this example. Note that we use the option
1854itself to print out the error message (the <tt>error</tt> method always returns
1855true) in order to get a nice error message (shown below). Now that we have our
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1856parser class, we can use it like this:</p>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1857
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]1858<div class="doc_code"><pre>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1859<b>static</b> <a href="#cl::opt">cl::opt</a>&lt;<b>unsigned</b>, <b>false</b>, FileSizeParser&gt;
1860MFS(<i>"max-file-size"</i>, <a href="#cl::desc">cl::desc</a>(<i>"Maximum file size to accept"</i>),
1861 <a href="#cl::value_desc">cl::value_desc</a>("<i>size</i>"));
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]1862</pre></div>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1863
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1864<p>Which adds this to the output of our program:</p>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1865
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]1866<div class="doc_code"><pre>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1867OPTIONS:
1868 -help - display available options (--help-hidden for more)
1869 ...
1870 <b>-max-file-size=&lt;size&gt; - Maximum file size to accept</b>
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]1871</pre></div>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1872
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1873<p>And we can test that our parse works correctly now (the test program just
1874prints out the max-file-size argument value):</p>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1875
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]1876<div class="doc_code"><pre>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1877$ ./test
1878MFS: 0
1879$ ./test -max-file-size=123MB
1880MFS: 128974848
1881$ ./test -max-file-size=3G
1882MFS: 3221225472
1883$ ./test -max-file-size=dog
1884-max-file-size option: 'dog' value invalid for file size argument!
Misha Brukmanf75c4b42005-03-11 00:00:33 +0000[diff] [blame]1885</pre></div>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1886
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1887<p>It looks like it works. The error message that we get is nice and helpful,
1888and we seem to accept reasonable file sizes. This wraps up the "custom parser"
1889tutorial.</p>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1890
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1891</div>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1892
1893<!-- ======================================================================= -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1894<div class="doc_subsection">
1895 <a name="explotingexternal">Exploiting external storage</a>
1896</div>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1897
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1898<div class="doc_text">
Reid Spencerb993feb2004-08-30 05:56:51 +0000[diff] [blame]1899 <p>Several of the LLVM libraries define static <tt>cl::opt</tt> instances that
1900 will automatically be included in any program that links with that library.
1901 This is a feature. However, sometimes it is necessary to know the value of the
1902 command line option outside of the library. In these cases the library does or
1903 should provide an external storage location that is accessible to users of the
1904 library. Examples of this include the <tt>llvm::DebugFlag</tt> exported by the
1905 <tt>lib/Support/Debug.cpp</tt> file and the <tt>llvm::TimePassesIsEnabled</tt>
1906 flag exported by the <tt>lib/VMCore/Pass.cpp</tt> file.</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1907
Reid Spencerb993feb2004-08-30 05:56:51 +0000[diff] [blame]1908<p>TODO: complete this section</p>
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1909
1910</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1911
1912<!-- ======================================================================= -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1913<div class="doc_subsection">
1914 <a name="dynamicopts">Dynamically adding command line options</a>
1915</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1916
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1917<div class="doc_text">
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1918
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1919<p>TODO: fill in this section</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]1920
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1921</div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]1922
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]1923<!-- *********************************************************************** -->
1924
1925<hr>
Misha Brukmanc53aefb2004-05-12 18:42:35 +0000[diff] [blame]1926<address>
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1931
1932 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]1933 <a href="http://llvm.org">LLVM Compiler Infrastructure</a><br>
Misha Brukman3c299112003-11-07 18:11:14 +0000[diff] [blame]1934 Last modified: $Date$
Misha Brukmanc53aefb2004-05-12 18:42:35 +0000[diff] [blame]1935</address>
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1936
1937</body>
1938</html>