Issue #3139: Make buffer-interface thread-safe wrt. PyArg_ParseTuple,

by denying s# to parse objects that have a releasebuffer procedure,
and introducing s*.

More module might need to get converted to use s*.

1 files changed, 16 insertions, 0 deletions

diff --git a/Doc/c-api/arg.rst b/Doc/c-api/arg.rst
index 3deafdfbe0..5ceab58cd2 100644
--- a/Doc/c-api/arg.rst
+++ b/Doc/c-api/arg.rst
@@ -40,6 +40,14 @@ variable(s) whose address should be passed.
    other read-buffer compatible objects pass back a reference to the raw internal
    data representation.
 
+``s*`` (string, Unicode, or any buffer compatible object) [Py_buffer \*]
+  Similar to ``s#``, this code fills a Py_buffer structure provided by the caller.
+  The buffer gets locked, so that the caller can subsequently use the buffer even
+  inside a ``Py_BEGIN_ALLOW_THREADS`` block; the caller is responsible for calling
+  ``PyBuffer_Release`` with the structure after it has processed the data.
+
+  .. versionadded:: 2.6
+
 ``z`` (string or ``None``) [const char \*]
    Like ``s``, but the Python object may also be ``None``, in which case the C
    pointer is set to *NULL*.
@@ -47,6 +55,10 @@ variable(s) whose address should be passed.
 ``z#`` (string or ``None`` or any read buffer compatible object) [const char \*, int]
    This is to ``s#`` as ``z`` is to ``s``.
 
+``z*`` (string or ``None`` or any buffer compatible object) [Py_buffer*]
+   This is to ``s*`` as ``z`` is to ``s``.
+  .. versionadded:: 2.6
+
 ``u`` (Unicode object) [Py_UNICODE \*]
    Convert a Python Unicode object to a C pointer to a NUL-terminated buffer of
    16-bit Unicode (UTF-16) data.  As with ``s``, there is no need to provide
@@ -240,6 +252,10 @@ variable(s) whose address should be passed.
    single-segment buffer objects are accepted; :exc:`TypeError` is raised for all
    others.
 
+``w*`` (read-write byte-oriented buffer) [Py_buffer \*]
+   This is to ``w`` what ``s*`` is to ``s``.
+   .. versionadded:: 2.6
+
 ``(items)`` (tuple) [*matching-items*]
    The object must be a Python sequence whose length is the number of format units
    in *items*.  The C arguments must correspond to the individual format units in