[ python-Bugs-1659171 ] Calling tparm from extension lib fails in Python 2.5

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Bugs item #1659171, was opened at 2007-02-13 09:27
Message generated for change (Comment added) made by nnorwitz
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Category: Extension Modules
Group: None
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Richard B. Kreckel (richyk)
Assigned to: Nobody/Anonymous (nobody)
Summary: Calling tparm from extension lib fails in Python 2.5

Initial Comment:
Attached is a little C++ module that fetches the terminal capability string for turning off all attributes and runs it through tparm(). (All this is done in a static Ctor of a class without init function, but never mind.)

Compile with:
g++ -c testlib.cc
g++ testlib.o -o testlib.so -shared -Wl,-soname,testlib.so -lncurses

On SuSE Linux 10.1 (and older), I get the expected behavior:

Python 2.4.2 (#1, Oct 13 2006, 17:11:24) 
[GCC 4.1.0 (SUSE Linux)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import testlib
Terminal is "xterm"
Dump of sgr0: 1b 5b 30 6d
Dump of instance: 1b 5b 30 6d
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
ImportError: dynamic module does not define init function (inittestlib)
>>> 

However, on SuSE Linux 10.2, tparm creates a NULL pointer:
Python 2.5 (r25:51908, Jan  9 2007, 16:59:32) 
[GCC 4.1.2 20061115 (prerelease) (SUSE Linux)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import testlib
Terminal is "xterm"
Dump of sgr0: 1b 5b 30 6d
Rats! tparm made a NULL pointer!
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: dynamic module does not define init function (inittestlib)
>>> 

Why, oh why?


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>Comment By: Neal Norwitz (nnorwitz)
Date: 2007-02-25 14:16

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Can you test with 2.5 from SVN and confirm your program works in the
complete context?

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Comment By: Richard B. Kreckel (richyk)
Date: 2007-02-22 04:25

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The error message about the undefined init function is a red herring. The
example is actually a stripped-down testcase from a much larger
Boost.Python module, which of course does have an init function. The point
here is the NULL pointer returned by tparm.

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Comment By: Martin v. Löwis (loewis)
Date: 2007-02-14 13:24

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I fail to see the bug. The exception precisely describes the error in your
code

ImportError: dynamic module does not define init function (inittestlib)

Why do you expect any meaningful behavior in the presence of this error?
Your shared library isn't an extension module.

If you think it is related to #1548092, please try out the subversion
trunk, which has fixed this bug.

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Comment By: Richard B. Kreckel (richyk)
Date: 2007-02-14 00:52

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I suspect that this is a duplicate of Bug [1548092].
Note that, there it is asserted that tparm returns NULL on certain invalid
strings.
That does not seem to be true. It returns NULL for valid trivial strings,
too.


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