ltrace.1

.\" Copyright (c) 1997-2001 Juan Cespedes <cespedes@debian.org>
.\" This file is covered by the GNU GPL
.TH ltrace 1 
.SH NAME
ltrace \- A library call tracer

.SH SYNOPSIS
.B ltrace
.I "[-dfiLSrtttChV] [-a column] [-s strsize] [-o filename] [-n nr] [-l filename] [-u username] [-p pid] ... [-e expr] [--debug] [--demangle] [--align=column] [--output=filename] [--indent=nr] [--library=filename] [--help] [--version] [command [arg ...]]"

.SH DESCRIPTION
.B ltrace
is a program that simply runs the specified
.I command
until it exits.  It intercepts and records the dynamic library calls
which are called by the executed process and the signals which are
received by that process.
It can also intercept and print the system calls executed by the program.
.PP
Its use is very similar to
.BR strace(1) .

.SH OPTIONS
.TP
.I \-d, \-\-debug
Increase the debugging level.
.TP
.I \-f
Trace child processes as they are created by
currently  traced processes as a result of the fork(2)
or clone(2) system calls.
The new process is attached as soon as its pid is known.
.TP
.I \-i
Print the instruction pointer at the time of the library call.
.TP
.I \-L
DON'T display library calls (use it with the
.I \-S
option).
.TP
.I \-S
Display system calls as well as library calls
.TP
.I \-r
Print a relative timestamp with each line of the trace.
This records the time difference between the beginning of
successive lines.
.TP
.I \-t
Prefix each line of the trace with the time of day.
.TP
.I \-tt
If given twice, the time printed will include the microseconds.
.TP
.I \-ttt
If given thrice, the time printed will include the microseconds and
the leading portion will be printed as the number of seconds since the
epoch.
.TP
.I \-C, \-\-demangle
Decode (demangle) low-level symbol names into user-level names.
Besides removing any initial underscore prepended by the system,
this makes C++ function names readable.
.TP
.I \-a, \-\-align column
Align return values in a secific column (default column 50).
.TP
.I \-s
Specify the maximum string size to print (the default is 32).
.TP
.I \-o, \-\-output filename
Write the trace output to the file
.I filename
rather than to stderr.
.TP
.I \-n, \-\-indent nr
Indent trace output by
.I nr
number of spaces for each new nested call. Using this option makes
the program flow visualization easy to follow.
.TP
.I \-l, \-\-library filename
Display only the symbols included in the library
.I filename.
Up to 20 library names can be specified with several instances
of this option.
.TP
.I \-u username
Run command with the userid, groupid and supplementary groups of
.IR username .
This option is only useful when running as root and enables the
correct execution of setuid and/or setgid binaries.
.TP
.I \-p pid
Attach to the process with the process ID
.I pid
and begin tracing.
.TP
.I \-e expr
A qualifying expression which modifies which events to trace.
The format of the expression is:
.br
[!]value1[,value2]...
.br
where the values are the functions to trace.  Using an exclamation
mark negates the set of values.  For example
.I \-e printf
means to trace only the printf library call.  By contrast,
.I \-e !printf
means to trace every library call except printf.
.IP
Note that some shells use the exclamation point for history
expansion; even inside quoted arguments.  If so, you must escape
the exclamation point with a backslash.
.TP
.I \-h, \-\-help
Show a summary of the options to ltrace and exit.
.TP
.I \-V, \-\-version
Show the version number of ltrace and exit.

.SH BUGS
It has most of the bugs stated in
.BR strace(1) .
.LP
Manual page and documentation are not very up-to-date.
.LP
Option -f sometimes fails to trace some children.
.LP
It only works on Linux/i386, Linux/m68k, and Linux/arm
.LP
Only ELF32 binaries are supported
.PP
If you like to report a bug, send a notice to the author, or use the
.BR bug(1)
program if you are under the Debian GNU/Linux distribution.

.SH FILES
.TP
.I /etc/ltrace.conf
System configuration file
.TP
.I ~/.ltrace.conf
Personal config file, overrides
.I /etc/ltrace.conf

.SH AUTHOR
Juan Cespedes <cespedes@debian.org>

.SH "SEE ALSO"
.BR strace(1) ,
.BR ptrace(2)