Update of /cvsroot/py-howto/pyhowto
In directory usw-pr-cvs1:/tmp/cvs-serv14496
Modified Files:
python-21.tex
Log Message:
Add a paragraph about obmalloc turning up bugs in extension modules
Mention the new ports
Index: python-21.tex
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RCS file: /cvsroot/py-howto/pyhowto/python-21.tex,v
retrieving revision 1.20
retrieving revision 1.21
diff -C2 -r1.20 -r1.21
*** python-21.tex 2001/03/23 03:29:08 1.20
--- python-21.tex 2001/03/23 03:52:46 1.21
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requests from these pools. It can be enabled by providing the
\longprogramopt{with-pymalloc} option to the \program{configure} script; see
! \file{Objects/obmalloc.c} for the implementation details.
! Contributed by Vladimir Marangozov.
\item The speed of line-oriented file I/O has been improved because
people often complain about its lack of speed, and because it's often
--- 752,774 ----
requests from these pools. It can be enabled by providing the
\longprogramopt{with-pymalloc} option to the \program{configure} script; see
! \file{Objects/obmalloc.c} for the implementation details.
+ Authors of C extension modules should test their code with the object
+ allocator enabled, because some incorrect code may break, causing core
+ dumps at runtime. There are a bunch of memory allocation functions in
+ Python's C API that have previously been just aliases for the C
+ library's \function{malloc()} and \function{free()}, meaning that if
+ you accidentally called mismatched functions, the error wouldn't be
+ noticeable. When the object allocator is enabled, these functions
+ aren't aliases of \function{malloc()} and \function{free()} any more,
+ and calling the wrong function to free memory will get you a core
+ dump. For example, if memory was allocated using
+ \function{PyMem_New()}, it has to be freed using
+ \function{PyMem_Del()}, not \function{free()}. A few modules included
+ with Python fell afoul of this and had to be fixed; doubtless there
+ are more third-party modules that will have the same problem.
+
+ The object allocator was contributed by Vladimir Marangozov.
+
\item The speed of line-oriented file I/O has been improved because
people often complain about its lack of speed, and because it's often
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\item The size of the Unicode character database was shrunk by another
340K thanks to Fredrik Lundh.
+
+ \item Some new ports were contributed: MacOS X (by Steven Majewski),
+ Cygwin (by Jason Tishler); RISCOS (by Dietmar Schwertberger).
\end{itemize}
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