mirror of
https://github.com/python/cpython.git
synced 2025-10-30 21:21:22 +00:00
108 lines
3.9 KiB
C
108 lines
3.9 KiB
C
/* The PyMem_ family: low-level memory allocation interfaces.
|
|
See objimpl.h for the PyObject_ memory family.
|
|
*/
|
|
|
|
#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
|
|
use the functions, to ensure binary compatibility across Python versions.
|
|
Because the Python implementation is free to change internal details, and
|
|
the macros may (or may not) expose details for speed, if you do use the
|
|
macros you must recompile your extensions with each Python release.
|
|
|
|
Never mix calls to PyMem_ with calls to the platform malloc/realloc/
|
|
calloc/free. For example, on Windows different DLLs may end up using
|
|
different heaps, and if you use PyMem_Malloc you'll get the memory from the
|
|
heap used by the Python DLL; it could be a disaster if you free()'ed that
|
|
directly in your own extension. Using PyMem_Free instead ensures Python
|
|
can return the memory to the proper heap. As another example, in
|
|
PYMALLOC_DEBUG mode, Python wraps all calls to all PyMem_ and PyObject_
|
|
memory functions in special debugging wrappers that add additional
|
|
debugging info to dynamic memory blocks. The system routines have no idea
|
|
what to do with that stuff, and the Python wrappers have no idea what to do
|
|
with raw blocks obtained directly by the system routines then.
|
|
*/
|
|
|
|
/*
|
|
* Raw memory interface
|
|
* ====================
|
|
*/
|
|
|
|
/* Functions
|
|
|
|
Functions supplying platform-independent semantics for malloc/realloc/
|
|
free. 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).
|
|
*/
|
|
|
|
PyAPI_FUNC(void *) PyMem_Malloc(size_t);
|
|
PyAPI_FUNC(void *) PyMem_Realloc(void *, size_t);
|
|
PyAPI_FUNC(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. */
|
|
#ifdef PYMALLOC_DEBUG
|
|
/* Redirect all memory operations to Python's debugging allocator. */
|
|
#define PyMem_MALLOC PyObject_MALLOC
|
|
#define PyMem_REALLOC PyObject_REALLOC
|
|
|
|
#else /* ! PYMALLOC_DEBUG */
|
|
|
|
/* PyMem_MALLOC(0) means malloc(1). Some systems would return NULL
|
|
for malloc(0), which would be treated as an error. Some platforms
|
|
would return a pointer with no memory behind it, which would break
|
|
pymalloc. To solve these problems, allocate an extra byte. */
|
|
#define PyMem_MALLOC(n) malloc((n) ? (n) : 1)
|
|
#define PyMem_REALLOC(p, n) realloc((p), (n) ? (n) : 1)
|
|
|
|
#endif /* PYMALLOC_DEBUG */
|
|
|
|
/* In order to avoid breaking old code mixing PyObject_{New, NEW} with
|
|
PyMem_{Del, DEL} and PyMem_{Free, FREE}, the PyMem "release memory"
|
|
functions have to be redirected to the object deallocator. */
|
|
#define PyMem_FREE PyObject_FREE
|
|
|
|
/*
|
|
* Type-oriented memory interface
|
|
* ==============================
|
|
*
|
|
* These are carried along for historical reasons. There's rarely a good
|
|
* reason to use them anymore (you can just as easily do the multiply and
|
|
* cast yourself).
|
|
*/
|
|
|
|
#define PyMem_New(type, n) \
|
|
( (type *) PyMem_Malloc((n) * sizeof(type)) )
|
|
#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)) )
|
|
#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} and PyMem_{Free, FREE}, the PyMem "release memory"
|
|
functions have to be redirected to the object deallocator. */
|
|
#define PyMem_Del PyObject_Free
|
|
#define PyMem_DEL PyObject_FREE
|
|
|
|
#ifdef __cplusplus
|
|
}
|
|
#endif
|
|
|
|
#endif /* !Py_PYMEM_H */
|