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Copying 1.2.1 to be the new trunk
author adustman
date Sun, 02 Apr 2006 18:20:53 +0000
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1
2 /* The idea of this file is that you bundle it with your extension,
3 #include it, program to Python 2.3's memory API and have your
4 extension build with any version of Python from 1.5.2 through to
5 2.3 (and hopefully beyond). */
6
7 #ifndef Py_PYMEMCOMPAT_H
8 #define Py_PYMEMCOMPAT_H
9
10 #include "Python.h"
11
12 /* There are three "families" of memory API: the "raw memory", "object
13 memory" and "object" families. (This is ignoring the matter of the
14 cycle collector, about which more is said below).
15
16 Raw Memory:
17
18 PyMem_Malloc, PyMem_Realloc, PyMem_Free
19
20 Object Memory:
21
22 PyObject_Malloc, PyObject_Realloc, PyObject_Free
23
24 Object:
25
26 PyObject_New, PyObject_NewVar, PyObject_Del
27
28 The raw memory and object memory allocators both mimic the
29 malloc/realloc/free interface from ANSI C, but the object memory
30 allocator can (and, since 2.3, does by default) use a different
31 allocation strategy biased towards lots of lots of "small"
32 allocations.
33
34 The object family is used for allocating Python objects, and the
35 initializers take care of some basic initialization (setting the
36 refcount to 1 and filling out the ob_type field) as well as having
37 a somewhat different interface.
38
39 Do not mix the families! E.g. do not allocate memory with
40 PyMem_Malloc and free it with PyObject_Free. You may get away with
41 it quite a lot of the time, but there *are* scenarios where this
42 will break. You Have Been Warned.
43
44 Also, in many versions of Python there are an insane amount of
45 memory interfaces to choose from. Use the ones described above. */
46
47 #if PY_VERSION_HEX < 0x01060000
48 /* raw memory interface already present */
49
50 /* there is no object memory interface in 1.5.2 */
51 #define PyObject_Malloc PyMem_Malloc
52 #define PyObject_Realloc PyMem_Realloc
53 #define PyObject_Free PyMem_Free
54
55 /* the object interface is there, but the names have changed */
56 #define PyObject_New PyObject_NEW
57 #define PyObject_NewVar PyObject_NEW_VAR
58 #define PyObject_Del PyMem_Free
59 #endif
60
61 /* If your object is a container you probably want to support the
62 cycle collector, which was new in Python 2.0.
63
64 Unfortunately, the interface to the collector that was present in
65 Python 2.0 and 2.1 proved to be tricky to use, and so changed in
66 2.2 -- in a way that can't easily be papered over with macros.
67
68 This file contains macros that let you program to the 2.2 GC API.
69 Your module will compile against any Python since version 1.5.2,
70 but the type will only participate in the GC in versions 2.2 and
71 up. Some work is still necessary on your part to only fill out the
72 tp_traverse and tp_clear fields when they exist and set tp_flags
73 appropriately.
74
75 It is possible to support both the 2.0 and 2.2 GC APIs, but it's
76 not pretty and this comment block is too narrow to contain a
77 desciption of what's required... */
78
79 #if PY_VERSION_HEX < 0x020200B1
80 #define PyObject_GC_New PyObject_New
81 #define PyObject_GC_NewVar PyObject_NewVar
82 #define PyObject_GC_Del PyObject_Del
83 #define PyObject_GC_Track(op)
84 #define PyObject_GC_UnTrack(op)
85 #endif
86
87 #endif /* !Py_PYMEMCOMPAT_H */