[Python-bugs-list] [ python-Bugs-478339 ] Linking/compiling with DEBUG

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Bugs item #478339, was opened at 2001-11-05 07:45
You can respond by visiting: 
http://sourceforge.net/tracker/?func=detail&atid=105470&aid=478339&group_id=5470

Category: Python Library
Group: Python 2.1.1
Status: Open
Resolution: None
Priority: 5
Submitted By: Nobody/Anonymous (nobody)
Assigned to: Nobody/Anonymous (nobody)
Summary: Linking/compiling with DEBUG

Initial Comment:
I have an embedded use of the Python interpreter. I
want to compile and link the encapsulating application with
and without DEBUG. I have disabled the use of the
pragma in config.h to always use the library specified
in the link statement, which is always the standard
python library. I have ensured that all invocations of
Python.h undefine the DEBUG symbol before including them.

Compiling the application without debug: works fine if
you link non-debug. However, linking with debug causes
some change in the way python modules are looked up and
I'm getting undefined local modules. I have checked the
PYTHONPATH environment variable and it is correct, and
the .py module exists in the correct directory. (This
is a common scenario where some libraries are compiled
without DEBUG, some with DEBUG, and then the whole
application linked DEBUG.)

Compiling the application with debug: Link errors
result. Undefined -- _Py_RefTotal, _Py_Dealloc,
_PyInitModule4TraceRefs.

Python is making too many hidden assumptions about the
build environment when it is being used embedded. This
is a critical problem as it makes it impossible to
build the encapsulating application for debug purposes.

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>Comment By: Martin v. Löwis (loewis)
Date: 2001-11-07 14:11

Message:
Logged In: YES 
user_id=21627

I cannot understand what bug you are reporting. Of the
things you report, which of them did you not expect?

For example, that Py_RefTotal is undefined when you compile
with DEBUG, but link with the no-debug library is not a bug,
but by design: those functions are used in every debug
module, but available only in the debug library.

Your complete compilation approach is flawed: If you compile
with pydebug, you absolutely *must* link with the debug
library: the object layout of every object will change, so
crashes are likely if you link with the wrong library.

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Comment By: Nobody/Anonymous (nobody)
Date: 2001-11-05 09:29

Message:
Logged In: NO 

More info: I've now narrowed it down to the fact that when
the final link is done with debug, the PYTHONPATH
environment variable is ignored altogether. In my case, I
cannot rely on the registry being set up for Python, and the
system is resorting to the default relative path names
(which, in my case, are of no use).

How does the behavior of the (non-debug) python library know
to change based on the final link? And why is PYTHONPATH
ignored if it is linked in debug?

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