Misc/AIX-NOTES - platform/external/python/cpython2 - Gitiles

 Subject: AIX - Misc/AIX-NOTES
 From: Vladimir Marangozov <Vladimir.Marangozov@imag.fr>
 To: guido@CNRI.Reston.Va.US (Guido van Rossum)
 Date: Wed, 6 Aug 1997 11:41:00 +0200 (EET)

 ==============================================================================
                               COMPILER INFORMATION
 ------------------------------------------------------------------------------

 (1) A problem has been reported with "make test" failing because of "weird
     indentation."  Searching the comp.lang.python newsgroup reveals several
     threads on this subject, and it seems to be a compiler bug in an old
     version of the AIX CC compiler.  However, the compiler/OS combination
     which has this problem is not identified.  In preparation for the 1.4
     release, Vladimir Marangozov (Vladimir.Marangozov@imag.fr) and Manus Hand
     (mhand@csn.net) reported no such troubles for the following compilers and
     operating system versions:
        AIX C compiler version 3.1.2 on AIX 4.1.3 and AIX 4.1.4
        AIX C compiler version 1.3.0 on AIX 3.2.5
     If you have this problem, please report the compiler/OS version.

 (2) Stefan Esser (se@MI.Uni-Koeln.DE), in work done to compile Python
     1.0.0 on AIX 3.2.4, reports that AIX compilers don't like the LANG
     environment varaiable set to European locales.  This makes the compiler
     generate floating point constants using "," as the decimal seperator,
     which the assembler doesn't understand (or perhaps it is the other way
     around, with the assembler expecting, but not getting "," in float
     numbers).  "LANG=C; export LANG" solves the problem, as does
     "LANG=C $(MAKE) ..." in the master Makefile.

 (3) The cc (or xlc) compiler considers "Python/ceval.c" too complex to
     optimize, except when invoked with "-qmaxmem=4000"

 (4) Some problems (due to _AIX not being #defined) when python 1.0.0 was
     compiled using 'gcc -ansi' were reported by Stefan Esser, but were not
     investigated.

 (5) The cc compiler has internal variables named "__abs" and "__div".  These
     names are reserved and may not be used as program variables in compiled
     source.  (As an anecdote in support of this, the implementation of
     Python/operator.c had this problem in the 1.4 beta releases, and the
     solution was to re#define some core-source variables having these names,
     to give these python variables different names if the build is being done
     on AIX.)

 (6) As mentioned in the README, builds done immediately after previous builds
     (without "make clean" or "make clobber") sometimes fail for mysterious
     reasons.  There are some unpredictable results when the configuration
     is changed (that is, if you "configure" with different parameters) or if
     intermediate changes are made to some files.  Performing "make clean" or
     "make clobber" resolves the problems.

 ==============================================================================
                                 THREAD SUPPORT
 ------------------------------------------------------------------------------

 As of AIX version 4, there are two (incompatible) types of pthreads on AIX:
         a)  AIX DCE pthreads (on AIX 3.2.5)
         b)  AIX 4 pthreads (on AIX 4.1 and up)
 Support has been added to Python to handle the distinction.

 The cc and gcc compilers do not initialize pthreads properly. The only
 compilers that can initialize pthreads properly are IBM *_r* compilers,
 which use the crt0_r.o module, and which invoke ld with the reentrant
 version of libc (libc_r).

 In order to enable thread support, follow these steps:
    1.  Uncomment the thread module in Modules/Setup
    2.  configure --without-gcc --with-thread ...
    3.  make CC="cc_r" OPT="-O -qmaxmem=4000"

 For example, to make with both threads and readline, use:
   ./configure --without-gcc --with-thread --with-readline=/usr/local/lib
   make CC=cc_r OPT="-O2 -qmaxmem=4000"

 If the "make" which is used ignores the "CC=cc_r" directive, one could alias
 the cc command to cc_r (for example, in C-shell, perform an "alias cc cc_r").

 Vladimir Marangozov (Vladimir.Marangozov@imag.fr) provided this information,
 and he reports that a cc_r build initializes threads properly and that all
 demos on threads run okay with cc_r.

 ==============================================================================
                             SHARED LIBRARY SUPPORT
 ------------------------------------------------------------------------------

 AIX shared library support was added to Python in the 1.4 release by Manus
 Hand (mhand@csn.net) and Vladimir Marangozov (Vladimir.Marangozov@imag.fr).

 Python modules may now be built as shared libraries on AIX using the normal
 process of uncommenting the "*shared*" line in Modules/Setup before the
 build.

 AIX shared libraries require that an "export" and "import" file be provided
 at compile time to list all extern symbols which may be shared between
 modules.  The "export" file (named python.exp) for the modules and the
 libraries that belong to the Python core is created by the "makexp_aix"
 script before performing the link of the python binary. It lists all global
 symbols (exported during the link) of the modules and the libraries that
 make up the python executable.

 When shared library modules (.so files) are made, a second shell script
 is invoked.  This script is named "ld_so_aix" and is also provided with
 the distribution in the Modules subdirectory.  This script acts as an "ld"
 wrapper which hides the explicit management of "export" and "import" files;
 it adds the appropriate arguments (in the appropriate order) to the link
 command that creates the shared module.  Among other things, it specifies
 that the "python.exp" file is an "import" file for the shared module.

 At the time of this writing, neither the python.exp file nor the makexp_aix
 or ld_so_aix scripts are installed by the make procedure, so you should
 remember to keep these and/or copy them to a different location for
 safekeeping if you wish to use them to add shared extension modules to
 python.  However, if the make process has been updated since this writing,
 these files MAY have been installed for you during the make by the
 LIBAINSTALL rule, in which case the need to make safe copies is obviated.

 If you wish to add a shared extension module to the language, you would follow
 the steps given in the example below (the example adds the shared extension
 module "spam" to python):
     1.  Make sure that "ld_so_aix" and "makexp_aix" are in your path.
     2.  The "python.exp" file should be in the current directory.
     3.  Issue the following commands or include them in your Makefile:
             cc -c spammodule.c
             ld_so_aix cc spammodule.o -o spammodule.so

 For more detailed information on the shared library support, examine the
 contents of the "ld_so_aix" and "makexp_aix" scripts or refer to the AIX
 documentation.

 NOTE:  If the extension module is written in C++ and contains templates,
        an alternative to "ld_so_aix" is the /usr/lpp/xlC/bin/makeC++SharedLib
        script.  Chris Myers (myers@TC.Cornell.EDU) reports that ld_so_aix
        works well for some C++ (including the C++ that is generated
        automatically by the Python SWIG package [SWIG can be found at
        http://www.cs.utah.edu/~beazley/SWIG/swig.html]).  However, it is not
        known whether makeC++SharedLib can be used as a complete substitute
        for ld_so_aix.

 According to Gary Hook from IBM, the format of the export file changed
 in AIX 4.2.  For AIX 4.2 and later, a period "." is required on the
 first line after "#!".  If python crashes while importing a shared
 library, you can try modifying the LINKCC variable in the Makefile.
 It probably looks like this:

 	LINKCC=     $(srcdir)/Modules/makexp_aix Modules/python.exp \"\" $(LIBRARY); $(PURIFY) $(CXX)

 You should modify the \"\" to be a period:

 	LINKCC=     $(srcdir)/Modules/makexp_aix Modules/python.exp . $(LIBRARY); $(PURIFY) $(CXX)

 Using a period fixed the problem in the snake farm.  YMMV.
 After testing with different versions of AIX, a fix should
 be checked in.  Hopefully, this fix be incorporated into Python 2.3.

 ==============================================================================
	Subject: AIX - Misc/AIX-NOTES
	From: Vladimir Marangozov <Vladimir.Marangozov@imag.fr>
	To: guido@CNRI.Reston.Va.US (Guido van Rossum)
	Date: Wed, 6 Aug 1997 11:41:00 +0200 (EET)

	==============================================================================
	COMPILER INFORMATION
	------------------------------------------------------------------------------

	(1) A problem has been reported with "make test" failing because of "weird
	indentation." Searching the comp.lang.python newsgroup reveals several
	threads on this subject, and it seems to be a compiler bug in an old
	version of the AIX CC compiler. However, the compiler/OS combination
	which has this problem is not identified. In preparation for the 1.4
	release, Vladimir Marangozov (Vladimir.Marangozov@imag.fr) and Manus Hand
	(mhand@csn.net) reported no such troubles for the following compilers and
	operating system versions:
	AIX C compiler version 3.1.2 on AIX 4.1.3 and AIX 4.1.4
	AIX C compiler version 1.3.0 on AIX 3.2.5
	If you have this problem, please report the compiler/OS version.

	(2) Stefan Esser (se@MI.Uni-Koeln.DE), in work done to compile Python
	1.0.0 on AIX 3.2.4, reports that AIX compilers don't like the LANG
	environment varaiable set to European locales. This makes the compiler
	generate floating point constants using "," as the decimal seperator,
	which the assembler doesn't understand (or perhaps it is the other way
	around, with the assembler expecting, but not getting "," in float
	numbers). "LANG=C; export LANG" solves the problem, as does
	"LANG=C $(MAKE) ..." in the master Makefile.

	(3) The cc (or xlc) compiler considers "Python/ceval.c" too complex to
	optimize, except when invoked with "-qmaxmem=4000"

	(4) Some problems (due to _AIX not being #defined) when python 1.0.0 was
	compiled using 'gcc -ansi' were reported by Stefan Esser, but were not
	investigated.

	(5) The cc compiler has internal variables named "__abs" and "__div". These
	names are reserved and may not be used as program variables in compiled
	source. (As an anecdote in support of this, the implementation of
	Python/operator.c had this problem in the 1.4 beta releases, and the
	solution was to re#define some core-source variables having these names,
	to give these python variables different names if the build is being done
	on AIX.)

	(6) As mentioned in the README, builds done immediately after previous builds
	(without "make clean" or "make clobber") sometimes fail for mysterious
	reasons. There are some unpredictable results when the configuration
	is changed (that is, if you "configure" with different parameters) or if
	intermediate changes are made to some files. Performing "make clean" or
	"make clobber" resolves the problems.

	==============================================================================
	THREAD SUPPORT
	------------------------------------------------------------------------------

	As of AIX version 4, there are two (incompatible) types of pthreads on AIX:
	a) AIX DCE pthreads (on AIX 3.2.5)
	b) AIX 4 pthreads (on AIX 4.1 and up)
	Support has been added to Python to handle the distinction.

	The cc and gcc compilers do not initialize pthreads properly. The only
	compilers that can initialize pthreads properly are IBM _r compilers,
	which use the crt0_r.o module, and which invoke ld with the reentrant
	version of libc (libc_r).

	In order to enable thread support, follow these steps:
	1. Uncomment the thread module in Modules/Setup
	2. configure --without-gcc --with-thread ...
	3. make CC="cc_r" OPT="-O -qmaxmem=4000"

	For example, to make with both threads and readline, use:
	./configure --without-gcc --with-thread --with-readline=/usr/local/lib
	make CC=cc_r OPT="-O2 -qmaxmem=4000"

	If the "make" which is used ignores the "CC=cc_r" directive, one could alias
	the cc command to cc_r (for example, in C-shell, perform an "alias cc cc_r").

	Vladimir Marangozov (Vladimir.Marangozov@imag.fr) provided this information,
	and he reports that a cc_r build initializes threads properly and that all
	demos on threads run okay with cc_r.

	==============================================================================
	SHARED LIBRARY SUPPORT
	------------------------------------------------------------------------------

	AIX shared library support was added to Python in the 1.4 release by Manus
	Hand (mhand@csn.net) and Vladimir Marangozov (Vladimir.Marangozov@imag.fr).

	Python modules may now be built as shared libraries on AIX using the normal
	process of uncommenting the "shared" line in Modules/Setup before the
	build.

	AIX shared libraries require that an "export" and "import" file be provided
	at compile time to list all extern symbols which may be shared between
	modules. The "export" file (named python.exp) for the modules and the
	libraries that belong to the Python core is created by the "makexp_aix"
	script before performing the link of the python binary. It lists all global
	symbols (exported during the link) of the modules and the libraries that
	make up the python executable.

	When shared library modules (.so files) are made, a second shell script
	is invoked. This script is named "ld_so_aix" and is also provided with
	the distribution in the Modules subdirectory. This script acts as an "ld"
	wrapper which hides the explicit management of "export" and "import" files;
	it adds the appropriate arguments (in the appropriate order) to the link
	command that creates the shared module. Among other things, it specifies
	that the "python.exp" file is an "import" file for the shared module.

	At the time of this writing, neither the python.exp file nor the makexp_aix
	or ld_so_aix scripts are installed by the make procedure, so you should
	remember to keep these and/or copy them to a different location for
	safekeeping if you wish to use them to add shared extension modules to
	python. However, if the make process has been updated since this writing,
	these files MAY have been installed for you during the make by the
	LIBAINSTALL rule, in which case the need to make safe copies is obviated.

	If you wish to add a shared extension module to the language, you would follow
	the steps given in the example below (the example adds the shared extension
	module "spam" to python):
	1. Make sure that "ld_so_aix" and "makexp_aix" are in your path.
	2. The "python.exp" file should be in the current directory.
	3. Issue the following commands or include them in your Makefile:
	cc -c spammodule.c
	ld_so_aix cc spammodule.o -o spammodule.so

	For more detailed information on the shared library support, examine the
	contents of the "ld_so_aix" and "makexp_aix" scripts or refer to the AIX
	documentation.

	NOTE: If the extension module is written in C++ and contains templates,
	an alternative to "ld_so_aix" is the /usr/lpp/xlC/bin/makeC++SharedLib
	script. Chris Myers (myers@TC.Cornell.EDU) reports that ld_so_aix
	works well for some C++ (including the C++ that is generated
	automatically by the Python SWIG package [SWIG can be found at
	http://www.cs.utah.edu/~beazley/SWIG/swig.html]). However, it is not
	known whether makeC++SharedLib can be used as a complete substitute
	for ld_so_aix.

	According to Gary Hook from IBM, the format of the export file changed
	in AIX 4.2. For AIX 4.2 and later, a period "." is required on the
	first line after "#!". If python crashes while importing a shared
	library, you can try modifying the LINKCC variable in the Makefile.
	It probably looks like this:

	LINKCC= $(srcdir)/Modules/makexp_aix Modules/python.exp \"\" $(LIBRARY); $(PURIFY) $(CXX)

	You should modify the \"\" to be a period:

	LINKCC= $(srcdir)/Modules/makexp_aix Modules/python.exp . $(LIBRARY); $(PURIFY) $(CXX)

	Using a period fixed the problem in the snake farm. YMMV.
	After testing with different versions of AIX, a fix should
	be checked in. Hopefully, this fix be incorporated into Python 2.3.

	==============================================================================