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cpython/Include/pymem.h
Tim Peters af3e8de580 First stab at rationalizing the PyMem_ API. Mixing PyObject_xyz with
PyMem_{Del, DEL} doesn't work yet (compilation problems).

pyport.h:  _PyMem_EXTRA is gone.

pmem.h:  Repaired comments.  PyMem_{Malloc, MALLOC} and
PyMem_{Realloc, REALLOC} now make the same x-platform guarantees when
asking for 0 bytes, and when passing a NULL pointer to the latter.

object.c:  PyMem_{Malloc, Realloc} just call their macro versions
now, since the latter take care of the x-platform 0 and NULL stuff
by themselves now.

pypcre.c, grow_stack():  So sue me.  On two lines, this called
PyMem_RESIZE to grow a "const" area.  It's not legit to realloc a
const area, so the compiler warned given the new expansion of
PyMem_RESIZE.  It would have gotten the same warning before if it
had used PyMem_Resize() instead; the older macro version, but not the
function version, silently cast away the constness.  IMO that was a wrong
thing to do, and the docs say the macro versions of PyMem_xyz are
deprecated anyway.  If somebody else is resizing const areas with the
macro spelling, they'll get a warning when they recompile now too.
2002-04-12 07:22:56 +00:00

113 lines
3.5 KiB
C

/* Lowest-level memory allocation interface */
#ifndef Py_PYMEM_H
#define Py_PYMEM_H
#include "pyport.h"
#ifdef __cplusplus
extern "C" {
#endif
/* BEWARE:
Each interface exports both functions and macros. Extension modules
should normally use the functions for ensuring binary compatibility
of the user's code across Python versions. Subsequently, if the
Python runtime switches to its own malloc (different from standard
malloc), no recompilation is required for the extensions.
The macro versions are free to trade compatibility for speed, although
there's no guarantee they're ever faster. Extensions shouldn't use the
macro versions, as they don't gurantee binary compatibility across
releases.
Do not mix calls to PyMem_xyz with calls to platform
malloc/realloc/calloc/free. */
/*
* Raw memory interface
* ====================
*/
/* Functions */
/* Functions supplying platform-independent semantics for malloc/realloc/
free; useful if you need to be sure you're using the same memory
allocator as Python (this can be especially important on Windows, if
you need to make sure you're using the same MS malloc/free, and out of
the same heap, as the main Python DLL uses).
These functions make sure that allocating 0 bytes returns a distinct
non-NULL pointer (whenever possible -- if we're flat out of memory, NULL
may be returned), even if the platform malloc and realloc don't.
Returned pointers must be checked for NULL explicitly. No action is
performed on failure (no exception is set, no warning is printed, etc).` */
extern DL_IMPORT(void *) PyMem_Malloc(size_t);
extern DL_IMPORT(void *) PyMem_Realloc(void *, size_t);
extern DL_IMPORT(void) PyMem_Free(void *);
/* Starting from Python 1.6, the wrappers Py_{Malloc,Realloc,Free} are
no longer supported. They used to call PyErr_NoMemory() on failure. */
/* Macros. */
#ifndef PyMem_MALLOC
#ifdef MALLOC_ZERO_RETURNS_NULL
#define PyMem_MALLOC(n) malloc((n) ? (n) : 1)
#else
#define PyMem_MALLOC malloc
#endif
/* Caution: whether MALLOC_ZERO_RETURNS_NULL is #defined has nothing to
do with whether platform realloc(non-NULL, 0) normally frees the memory
or returns NULL. Rather than introduce yet another config variation,
just make a realloc to 0 bytes act as if to 1 instead. */
#define PyMem_REALLOC(p, n) realloc((p), (n) ? (n) : 1)
#define PyMem_FREE free
#endif /* PyMem_MALLOC */
/*
* Type-oriented memory interface
* ==============================
*
* These are carried along for historical reasons. There's rarely a good
* reason to use them anymore.
*/
/* Functions */
#define PyMem_New(type, n) \
( (type *) PyMem_Malloc((n) * sizeof(type)) )
#define PyMem_Resize(p, type, n) \
( (p) = (type *) PyMem_Realloc((p), (n) * sizeof(type)) )
/* In order to avoid breaking old code mixing PyObject_{New, NEW} with
PyMem_{Del, DEL} (there was no choice about this in 1.5.2), the latter
have to be redirected to the object allocator. */
/* XXX The parser module needs rework before this can be enabled. */
#if 0
#define PyMem_Del PyObject_Free
#else
#define PyMem_Del PyMem_Free
#endif
/* Macros */
#define PyMem_NEW(type, n) \
( (type *) PyMem_MALLOC((n) * sizeof(type)) )
#define PyMem_RESIZE(p, type, n) \
( (p) = (type *) PyMem_REALLOC((p), (n) * sizeof(type)) )
/* XXX The parser module needs rework before this can be enabled. */
#if 0
#define PyMem_DEL PyObject_FREE
#else
#define PyMem_DEL PyMem_FREE
#endif
#ifdef __cplusplus
}
#endif
#endif /* !Py_PYMEM_H */