1
Subject: AIX - Misc/AIX-NOTES
2
From: Vladimir Marangozov <Vladimir.Marangozov@imag.fr>
3
To: guido@CNRI.Reston.Va.US (Guido van Rossum)
4
Date: Wed, 6 Aug 1997 11:41:00 +0200 (EET)
6
==============================================================================
8
------------------------------------------------------------------------------
10
(1) A problem has been reported with "make test" failing because of "weird
11
indentation." Searching the comp.lang.python newsgroup reveals several
12
threads on this subject, and it seems to be a compiler bug in an old
13
version of the AIX CC compiler. However, the compiler/OS combination
14
which has this problem is not identified. In preparation for the 1.4
15
release, Vladimir Marangozov (Vladimir.Marangozov@imag.fr) and Manus Hand
16
(mhand@csn.net) reported no such troubles for the following compilers and
17
operating system versions:
18
AIX C compiler version 3.1.2 on AIX 4.1.3 and AIX 4.1.4
19
AIX C compiler version 1.3.0 on AIX 3.2.5
20
If you have this problem, please report the compiler/OS version.
22
(2) Stefan Esser (se@MI.Uni-Koeln.DE), in work done to compile Python
23
1.0.0 on AIX 3.2.4, reports that AIX compilers don't like the LANG
24
environment varaiable set to European locales. This makes the compiler
25
generate floating point constants using "," as the decimal separator,
26
which the assembler doesn't understand (or perhaps it is the other way
27
around, with the assembler expecting, but not getting "," in float
28
numbers). "LANG=C; export LANG" solves the problem, as does
29
"LANG=C $(MAKE) ..." in the master Makefile.
31
(3) The cc (or xlc) compiler considers "Python/ceval.c" too complex to
32
optimize, except when invoked with "-qmaxmem=4000"
34
(4) Some problems (due to _AIX not being #defined) when python 1.0.0 was
35
compiled using 'gcc -ansi' were reported by Stefan Esser, but were not
38
(5) The cc compiler has internal variables named "__abs" and "__div". These
39
names are reserved and may not be used as program variables in compiled
40
source. (As an anecdote in support of this, the implementation of
41
Python/operator.c had this problem in the 1.4 beta releases, and the
42
solution was to re#define some core-source variables having these names,
43
to give these python variables different names if the build is being done
46
(6) As mentioned in the README, builds done immediately after previous builds
47
(without "make clean" or "make clobber") sometimes fail for mysterious
48
reasons. There are some unpredictable results when the configuration
49
is changed (that is, if you "configure" with different parameters) or if
50
intermediate changes are made to some files. Performing "make clean" or
51
"make clobber" resolves the problems.
53
==============================================================================
55
------------------------------------------------------------------------------
57
As of AIX version 4, there are two (incompatible) types of pthreads on AIX:
58
a) AIX DCE pthreads (on AIX 3.2.5)
59
b) AIX 4 pthreads (on AIX 4.1 and up)
60
Support has been added to Python to handle the distinction.
62
The cc and gcc compilers do not initialize pthreads properly. The only
63
compilers that can initialize pthreads properly are IBM *_r* compilers,
64
which use the crt0_r.o module, and which invoke ld with the reentrant
65
version of libc (libc_r).
67
In order to enable thread support, follow these steps:
68
1. Uncomment the thread module in Modules/Setup
69
2. configure --without-gcc --with-thread ...
70
3. make CC="cc_r" OPT="-O -qmaxmem=4000"
72
For example, to make with both threads and readline, use:
73
./configure --without-gcc --with-thread --with-readline=/usr/local/lib
74
make CC=cc_r OPT="-O2 -qmaxmem=4000"
76
If the "make" which is used ignores the "CC=cc_r" directive, one could alias
77
the cc command to cc_r (for example, in C-shell, perform an "alias cc cc_r").
79
Vladimir Marangozov (Vladimir.Marangozov@imag.fr) provided this information,
80
and he reports that a cc_r build initializes threads properly and that all
81
demos on threads run okay with cc_r.
83
==============================================================================
84
SHARED LIBRARY SUPPORT
85
------------------------------------------------------------------------------
87
AIX shared library support was added to Python in the 1.4 release by Manus
88
Hand (mhand@csn.net) and Vladimir Marangozov (Vladimir.Marangozov@imag.fr).
90
Python modules may now be built as shared libraries on AIX using the normal
91
process of uncommenting the "*shared*" line in Modules/Setup before the
94
AIX shared libraries require that an "export" and "import" file be provided
95
at compile time to list all extern symbols which may be shared between
96
modules. The "export" file (named python.exp) for the modules and the
97
libraries that belong to the Python core is created by the "makexp_aix"
98
script before performing the link of the python binary. It lists all global
99
symbols (exported during the link) of the modules and the libraries that
100
make up the python executable.
102
When shared library modules (.so files) are made, a second shell script
103
is invoked. This script is named "ld_so_aix" and is also provided with
104
the distribution in the Modules subdirectory. This script acts as an "ld"
105
wrapper which hides the explicit management of "export" and "import" files;
106
it adds the appropriate arguments (in the appropriate order) to the link
107
command that creates the shared module. Among other things, it specifies
108
that the "python.exp" file is an "import" file for the shared module.
110
At the time of this writing, neither the python.exp file nor the makexp_aix
111
or ld_so_aix scripts are installed by the make procedure, so you should
112
remember to keep these and/or copy them to a different location for
113
safekeeping if you wish to use them to add shared extension modules to
114
python. However, if the make process has been updated since this writing,
115
these files MAY have been installed for you during the make by the
116
LIBAINSTALL rule, in which case the need to make safe copies is obviated.
118
If you wish to add a shared extension module to the language, you would follow
119
the steps given in the example below (the example adds the shared extension
120
module "spam" to python):
121
1. Make sure that "ld_so_aix" and "makexp_aix" are in your path.
122
2. The "python.exp" file should be in the current directory.
123
3. Issue the following commands or include them in your Makefile:
125
ld_so_aix cc spammodule.o -o spammodule.so
127
For more detailed information on the shared library support, examine the
128
contents of the "ld_so_aix" and "makexp_aix" scripts or refer to the AIX
131
NOTE: If the extension module is written in C++ and contains templates,
132
an alternative to "ld_so_aix" is the /usr/lpp/xlC/bin/makeC++SharedLib
133
script. Chris Myers (myers@TC.Cornell.EDU) reports that ld_so_aix
134
works well for some C++ (including the C++ that is generated
135
automatically by the Python SWIG package [SWIG can be found at
136
http://www.cs.utah.edu/~beazley/SWIG/swig.html]). However, it is not
137
known whether makeC++SharedLib can be used as a complete substitute
140
According to Gary Hook from IBM, the format of the export file changed
141
in AIX 4.2. For AIX 4.2 and later, a period "." is required on the
142
first line after "#!". If python crashes while importing a shared
143
library, you can try modifying the LINKCC variable in the Makefile.
144
It probably looks like this:
146
LINKCC= $(srcdir)/Modules/makexp_aix Modules/python.exp \"\" $(LIBRARY); $(PURIFY) $(CXX)
148
You should modify the \"\" to be a period:
150
LINKCC= $(srcdir)/Modules/makexp_aix Modules/python.exp . $(LIBRARY); $(PURIFY) $(CXX)
152
Using a period fixed the problem in the snake farm. YMMV.
153
This fix has been incorporated into Python 2.3.
155
==============================================================================