cpython/Doc/c-api/objbuffer.rst

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.. highlightlang:: c
Old Buffer Protocol
-------------------
.. deprecated:: 3.0
These functions were part of the "old buffer protocol" API in Python 2.
In Python 3, this protocol doesn't exist anymore but the functions are still
exposed to ease porting 2.x code. They act as a compatibility wrapper
around the :ref:`new buffer protocol <bufferobjects>`, but they don't give
you control over the lifetime of the resources acquired when a buffer is
exported.
Therefore, it is recommended that you call :c:func:`PyObject_GetBuffer`
(or the ``y*`` or ``w*`` :ref:`format codes <arg-parsing>` with the
:c:func:`PyArg_ParseTuple` family of functions) to get a buffer view over
an object, and :c:func:`PyBuffer_Release` when the buffer view can be released.
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.. c:function:: int PyObject_AsCharBuffer(PyObject *obj, const char **buffer, Py_ssize_t *buffer_len)
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Merged revisions 60481,60485,60489-60492,60494-60496,60498-60499,60501-60503,60505-60506,60508-60509,60523-60524,60532,60543,60545,60547-60548,60552,60554,60556-60559,60561-60562,60569,60571-60572,60574,60576-60583,60585-60586,60589,60591,60594-60595,60597-60598,60600-60601,60606-60612,60615,60617,60619-60621,60623-60625,60627-60629,60631,60633,60635,60647,60650,60652,60654,60656,60658-60659,60664-60666,60668-60670,60672,60676,60678,60680-60683,60685-60686,60688,60690,60692-60694,60697-60700,60705-60706,60708,60711,60714,60720,60724-60730,60732,60736,60742,60744,60746,60748,60750-60751,60753,60756-60757,60759-60761,60763-60764,60766,60769-60770,60774-60784,60787-60789,60793,60796,60799-60809,60812-60813,60815-60821,60823-60826,60828-60829,60831-60834,60836,60838-60839,60846-60849,60852-60854,60856-60859,60861-60870,60874-60875,60880-60881,60886,60888-60890,60892,60894-60898,60900-60931,60933-60958 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r60901 | eric.smith | 2008-02-19 14:21:56 +0100 (Tue, 19 Feb 2008) | 1 line Added PEP 3101. ........ r60907 | georg.brandl | 2008-02-20 20:12:36 +0100 (Wed, 20 Feb 2008) | 2 lines Fixes contributed by Ori Avtalion. ........ r60909 | eric.smith | 2008-02-21 00:34:22 +0100 (Thu, 21 Feb 2008) | 1 line Trim leading zeros from a floating point exponent, per C99. See issue 1600. As far as I know, this only affects Windows. Add float type 'n' to PyOS_ascii_formatd (see PEP 3101 for 'n' description). ........ r60910 | eric.smith | 2008-02-21 00:39:28 +0100 (Thu, 21 Feb 2008) | 1 line Now that PyOS_ascii_formatd supports the 'n' format, simplify the float formatting code to just call it. ........ r60918 | andrew.kuchling | 2008-02-21 15:23:38 +0100 (Thu, 21 Feb 2008) | 2 lines Close manifest file. This change doesn't make any difference to CPython, but is a necessary fix for Jython. ........ r60921 | guido.van.rossum | 2008-02-21 18:46:16 +0100 (Thu, 21 Feb 2008) | 2 lines Remove news about float repr() -- issue 1580 is still in limbo. ........ r60923 | guido.van.rossum | 2008-02-21 19:18:37 +0100 (Thu, 21 Feb 2008) | 5 lines Removed uses of dict.has_key() from distutils, and uses of callable() from copy_reg.py, so the interpreter now starts up without warnings when '-3' is given. More work like this needs to be done in the rest of the stdlib. ........ r60924 | thomas.heller | 2008-02-21 19:28:48 +0100 (Thu, 21 Feb 2008) | 4 lines configure.ac: Remove the configure check for _Bool, it is already done in the top-level Python configure script. configure, fficonfig.h.in: regenerated. ........ r60925 | thomas.heller | 2008-02-21 19:52:20 +0100 (Thu, 21 Feb 2008) | 3 lines Replace 'has_key()' with 'in'. Replace 'raise Error, stuff' with 'raise Error(stuff)'. ........ r60927 | raymond.hettinger | 2008-02-21 20:24:53 +0100 (Thu, 21 Feb 2008) | 1 line Update more instances of has_key(). ........ r60928 | guido.van.rossum | 2008-02-21 20:46:35 +0100 (Thu, 21 Feb 2008) | 3 lines Fix a few typos and layout glitches (more work is needed). Move 2.5 news to Misc/HISTORY. ........ r60936 | georg.brandl | 2008-02-21 21:33:38 +0100 (Thu, 21 Feb 2008) | 2 lines #2079: typo in userdict docs. ........ r60938 | georg.brandl | 2008-02-21 21:38:13 +0100 (Thu, 21 Feb 2008) | 2 lines Part of #2154: minimal syntax fixes in doc example snippets. ........ r60942 | raymond.hettinger | 2008-02-22 04:16:42 +0100 (Fri, 22 Feb 2008) | 1 line First draft for itertools.product(). Docs and other updates forthcoming. ........ r60955 | nick.coghlan | 2008-02-22 11:54:06 +0100 (Fri, 22 Feb 2008) | 1 line Try to make command line error messages from runpy easier to understand (and suppress traceback cruft from the implicitly invoked runpy machinery) ........ r60956 | georg.brandl | 2008-02-22 13:31:45 +0100 (Fri, 22 Feb 2008) | 2 lines A lot more typo fixes by Ori Avtalion. ........ r60957 | georg.brandl | 2008-02-22 13:56:34 +0100 (Fri, 22 Feb 2008) | 2 lines Don't reference pyshell. ........ r60958 | georg.brandl | 2008-02-22 13:57:05 +0100 (Fri, 22 Feb 2008) | 2 lines Another fix. ........
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Returns a pointer to a read-only memory location usable as character-based
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input. The *obj* argument must support the single-segment character buffer
Merged revisions 71920-71923,71925-71929,71931-71934,71937 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r71920 | jeroen.ruigrok | 2009-04-25 21:44:55 +0200 (za, 25 apr 2009) | 5 lines Issue #4129: More documentation pointers about int -> Py_ssize_t. Also fix up the documentation for PyObject_GC_Resize(). It seems that since it first got documented, the documentation was actually for _PyObject_GC_Resize(). ........ r71921 | jeroen.ruigrok | 2009-04-25 21:46:19 +0200 (za, 25 apr 2009) | 2 lines Issue #4129: Documentation notes for int -> Py_ssize_t changes. ........ r71922 | jeroen.ruigrok | 2009-04-25 21:49:05 +0200 (za, 25 apr 2009) | 2 lines Reformat, since I've been busy here anyway. ........ r71923 | jeroen.ruigrok | 2009-04-25 21:54:34 +0200 (za, 25 apr 2009) | 2 lines Issue #4129: Add a versionchanged notice for a few forgotten entries. ........ r71925 | jeroen.ruigrok | 2009-04-25 22:37:39 +0200 (za, 25 apr 2009) | 2 lines Since it's a macro, actually refer to it as such instead of function. ........ r71926 | jeroen.ruigrok | 2009-04-25 22:40:10 +0200 (za, 25 apr 2009) | 2 lines Reformat prior to editing. ........ r71927 | jeroen.ruigrok | 2009-04-25 22:41:40 +0200 (za, 25 apr 2009) | 2 lines Issue #4129: int -> Py_ssize_t documentation. ........ r71928 | jeroen.ruigrok | 2009-04-25 22:43:30 +0200 (za, 25 apr 2009) | 2 lines Reformat prior to editing. ........ r71929 | jeroen.ruigrok | 2009-04-25 22:44:58 +0200 (za, 25 apr 2009) | 2 lines Issue #4129: int -> Py_ssize_t documentation. ........ r71931 | jeroen.ruigrok | 2009-04-25 22:50:27 +0200 (za, 25 apr 2009) | 2 lines Issue #4129: int -> Py_ssize_t documentation. ........ r71932 | jeroen.ruigrok | 2009-04-25 22:55:39 +0200 (za, 25 apr 2009) | 2 lines Issue #4129: more int -> Py_ssize_t documentation. ........ r71933 | jeroen.ruigrok | 2009-04-25 22:58:35 +0200 (za, 25 apr 2009) | 2 lines Issue #4129: more int -> Py_ssize_t documentation. ........ r71934 | jeroen.ruigrok | 2009-04-25 23:02:34 +0200 (za, 25 apr 2009) | 2 lines Issue #4129: field changed from int to Py_ssize_t. ........ r71937 | jeroen.ruigrok | 2009-04-25 23:16:05 +0200 (za, 25 apr 2009) | 2 lines Issue #4129: document int -> Py_ssize_t changes. ........
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interface. On success, returns ``0``, sets *buffer* to the memory location
and *buffer_len* to the buffer length. Returns ``-1`` and sets a
:exc:`TypeError` on error.
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.. c:function:: int PyObject_AsReadBuffer(PyObject *obj, const void **buffer, Py_ssize_t *buffer_len)
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Merged revisions 71920-71923,71925-71929,71931-71934,71937 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r71920 | jeroen.ruigrok | 2009-04-25 21:44:55 +0200 (za, 25 apr 2009) | 5 lines Issue #4129: More documentation pointers about int -> Py_ssize_t. Also fix up the documentation for PyObject_GC_Resize(). It seems that since it first got documented, the documentation was actually for _PyObject_GC_Resize(). ........ r71921 | jeroen.ruigrok | 2009-04-25 21:46:19 +0200 (za, 25 apr 2009) | 2 lines Issue #4129: Documentation notes for int -> Py_ssize_t changes. ........ r71922 | jeroen.ruigrok | 2009-04-25 21:49:05 +0200 (za, 25 apr 2009) | 2 lines Reformat, since I've been busy here anyway. ........ r71923 | jeroen.ruigrok | 2009-04-25 21:54:34 +0200 (za, 25 apr 2009) | 2 lines Issue #4129: Add a versionchanged notice for a few forgotten entries. ........ r71925 | jeroen.ruigrok | 2009-04-25 22:37:39 +0200 (za, 25 apr 2009) | 2 lines Since it's a macro, actually refer to it as such instead of function. ........ r71926 | jeroen.ruigrok | 2009-04-25 22:40:10 +0200 (za, 25 apr 2009) | 2 lines Reformat prior to editing. ........ r71927 | jeroen.ruigrok | 2009-04-25 22:41:40 +0200 (za, 25 apr 2009) | 2 lines Issue #4129: int -> Py_ssize_t documentation. ........ r71928 | jeroen.ruigrok | 2009-04-25 22:43:30 +0200 (za, 25 apr 2009) | 2 lines Reformat prior to editing. ........ r71929 | jeroen.ruigrok | 2009-04-25 22:44:58 +0200 (za, 25 apr 2009) | 2 lines Issue #4129: int -> Py_ssize_t documentation. ........ r71931 | jeroen.ruigrok | 2009-04-25 22:50:27 +0200 (za, 25 apr 2009) | 2 lines Issue #4129: int -> Py_ssize_t documentation. ........ r71932 | jeroen.ruigrok | 2009-04-25 22:55:39 +0200 (za, 25 apr 2009) | 2 lines Issue #4129: more int -> Py_ssize_t documentation. ........ r71933 | jeroen.ruigrok | 2009-04-25 22:58:35 +0200 (za, 25 apr 2009) | 2 lines Issue #4129: more int -> Py_ssize_t documentation. ........ r71934 | jeroen.ruigrok | 2009-04-25 23:02:34 +0200 (za, 25 apr 2009) | 2 lines Issue #4129: field changed from int to Py_ssize_t. ........ r71937 | jeroen.ruigrok | 2009-04-25 23:16:05 +0200 (za, 25 apr 2009) | 2 lines Issue #4129: document int -> Py_ssize_t changes. ........
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Returns a pointer to a read-only memory location containing arbitrary data.
The *obj* argument must support the single-segment readable buffer
interface. On success, returns ``0``, sets *buffer* to the memory location
and *buffer_len* to the buffer length. Returns ``-1`` and sets a
:exc:`TypeError` on error.
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.. c:function:: int PyObject_CheckReadBuffer(PyObject *o)
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Returns ``1`` if *o* supports the single-segment readable buffer interface.
Otherwise returns ``0``. This function always succeeds.
Note that this function tries to get and release a buffer, and exceptions
which occur while calling corresponding functions will get suppressed.
To get error reporting use :c:func:`PyObject_GetBuffer()` instead.
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.. c:function:: int PyObject_AsWriteBuffer(PyObject *obj, void **buffer, Py_ssize_t *buffer_len)
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Returns a pointer to a writable memory location. The *obj* argument must
Merged revisions 71920-71923,71925-71929,71931-71934,71937 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r71920 | jeroen.ruigrok | 2009-04-25 21:44:55 +0200 (za, 25 apr 2009) | 5 lines Issue #4129: More documentation pointers about int -> Py_ssize_t. Also fix up the documentation for PyObject_GC_Resize(). It seems that since it first got documented, the documentation was actually for _PyObject_GC_Resize(). ........ r71921 | jeroen.ruigrok | 2009-04-25 21:46:19 +0200 (za, 25 apr 2009) | 2 lines Issue #4129: Documentation notes for int -> Py_ssize_t changes. ........ r71922 | jeroen.ruigrok | 2009-04-25 21:49:05 +0200 (za, 25 apr 2009) | 2 lines Reformat, since I've been busy here anyway. ........ r71923 | jeroen.ruigrok | 2009-04-25 21:54:34 +0200 (za, 25 apr 2009) | 2 lines Issue #4129: Add a versionchanged notice for a few forgotten entries. ........ r71925 | jeroen.ruigrok | 2009-04-25 22:37:39 +0200 (za, 25 apr 2009) | 2 lines Since it's a macro, actually refer to it as such instead of function. ........ r71926 | jeroen.ruigrok | 2009-04-25 22:40:10 +0200 (za, 25 apr 2009) | 2 lines Reformat prior to editing. ........ r71927 | jeroen.ruigrok | 2009-04-25 22:41:40 +0200 (za, 25 apr 2009) | 2 lines Issue #4129: int -> Py_ssize_t documentation. ........ r71928 | jeroen.ruigrok | 2009-04-25 22:43:30 +0200 (za, 25 apr 2009) | 2 lines Reformat prior to editing. ........ r71929 | jeroen.ruigrok | 2009-04-25 22:44:58 +0200 (za, 25 apr 2009) | 2 lines Issue #4129: int -> Py_ssize_t documentation. ........ r71931 | jeroen.ruigrok | 2009-04-25 22:50:27 +0200 (za, 25 apr 2009) | 2 lines Issue #4129: int -> Py_ssize_t documentation. ........ r71932 | jeroen.ruigrok | 2009-04-25 22:55:39 +0200 (za, 25 apr 2009) | 2 lines Issue #4129: more int -> Py_ssize_t documentation. ........ r71933 | jeroen.ruigrok | 2009-04-25 22:58:35 +0200 (za, 25 apr 2009) | 2 lines Issue #4129: more int -> Py_ssize_t documentation. ........ r71934 | jeroen.ruigrok | 2009-04-25 23:02:34 +0200 (za, 25 apr 2009) | 2 lines Issue #4129: field changed from int to Py_ssize_t. ........ r71937 | jeroen.ruigrok | 2009-04-25 23:16:05 +0200 (za, 25 apr 2009) | 2 lines Issue #4129: document int -> Py_ssize_t changes. ........
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support the single-segment, character buffer interface. On success,
returns ``0``, sets *buffer* to the memory location and *buffer_len* to the
buffer length. Returns ``-1`` and sets a :exc:`TypeError` on error.