Issue #26535: Correct docs regarding the struct buffer size
diff --git a/Doc/library/struct.rst b/Doc/library/struct.rst
index 12d4fbc..e757047 100644
--- a/Doc/library/struct.rst
+++ b/Doc/library/struct.rst
@@ -62,16 +62,16 @@
Unpack from the buffer *buffer* (presumably packed by ``pack(fmt, ...)``)
according to the format string *fmt*. The result is a tuple even if it
- contains exactly one item. The buffer must contain exactly the amount of
- data required by the format (``len(bytes)`` must equal ``calcsize(fmt)``).
+ contains exactly one item. The buffer's size in bytes must match the
+ size required by the format, as reflected by :func:`calcsize`.
.. function:: unpack_from(fmt, buffer, offset=0)
Unpack from *buffer* starting at position *offset*, according to the format
string *fmt*. The result is a tuple even if it contains exactly one
- item. *buffer* must contain at least the amount of data required by the
- format (``len(buffer[offset:])`` must be at least ``calcsize(fmt)``).
+ item. The buffer's size in bytes, minus *offset*, must be at least
+ the size required by the format, as reflected by :func:`calcsize`.
.. function:: iter_unpack(fmt, buffer)
@@ -79,8 +79,8 @@
Iteratively unpack from the buffer *buffer* according to the format
string *fmt*. This function returns an iterator which will read
equally-sized chunks from the buffer until all its contents have been
- consumed. The buffer's size in bytes must be a multiple of the amount
- of data required by the format, as reflected by :func:`calcsize`.
+ consumed. The buffer's size in bytes must be a multiple of the size
+ required by the format, as reflected by :func:`calcsize`.
Each iteration yields a tuple as specified by the format string.
@@ -389,7 +389,7 @@
.. method:: pack(v1, v2, ...)
Identical to the :func:`pack` function, using the compiled format.
- (``len(result)`` will equal :attr:`self.size`.)
+ (``len(result)`` will equal :attr:`size`.)
.. method:: pack_into(buffer, offset, v1, v2, ...)
@@ -400,19 +400,20 @@
.. method:: unpack(buffer)
Identical to the :func:`unpack` function, using the compiled format.
- (``len(buffer)`` must equal :attr:`self.size`).
+ The buffer's size in bytes must equal :attr:`size`.
.. method:: unpack_from(buffer, offset=0)
Identical to the :func:`unpack_from` function, using the compiled format.
- (``len(buffer[offset:])`` must be at least :attr:`self.size`).
+ The buffer's size in bytes, minus *offset*, must be at least
+ :attr:`size`.
.. method:: iter_unpack(buffer)
Identical to the :func:`iter_unpack` function, using the compiled format.
- (``len(buffer)`` must be a multiple of :attr:`self.size`).
+ The buffer's size in bytes must be a multiple of :attr:`size`.
.. versionadded:: 3.4
diff --git a/Modules/_struct.c b/Modules/_struct.c
index ffedb9f..f965541 100644
--- a/Modules/_struct.c
+++ b/Modules/_struct.c
@@ -1497,8 +1497,8 @@
"S.unpack(buffer) -> (v1, v2, ...)\n\
\n\
Return a tuple containing values unpacked according to the format\n\
-string S.format. Requires len(buffer) == S.size. See help(struct)\n\
-for more on format strings.");
+string S.format. The buffer's size in bytes must be S.size. See\n\
+help(struct) for more on format strings.");
static PyObject *
s_unpack(PyObject *self, PyObject *input)
@@ -1527,8 +1527,8 @@
"S.unpack_from(buffer, offset=0) -> (v1, v2, ...)\n\
\n\
Return a tuple containing values unpacked according to the format\n\
-string S.format. Requires len(buffer[offset:]) >= S.size. See\n\
-help(struct) for more on format strings.");
+string S.format. The buffer's size in bytes, minus offset, must be at\n\
+least S.size. See help(struct) for more on format strings.");
static PyObject *
s_unpack_from(PyObject *self, PyObject *args, PyObject *kwds)
@@ -2130,8 +2130,8 @@
"unpack(fmt, buffer) -> (v1, v2, ...)\n\
\n\
Return a tuple containing values unpacked according to the format string\n\
-fmt. Requires len(buffer) == calcsize(fmt). See help(struct) for more\n\
-on format strings.");
+fmt. The buffer's size in bytes must be calcsize(fmt). See help(struct)\n\
+for more on format strings.");
static PyObject *
unpack(PyObject *self, PyObject *args)
@@ -2153,8 +2153,8 @@
"unpack_from(fmt, buffer, offset=0) -> (v1, v2, ...)\n\
\n\
Return a tuple containing values unpacked according to the format string\n\
-fmt. Requires len(buffer[offset:]) >= calcsize(fmt). See help(struct)\n\
-for more on format strings.");
+fmt. The buffer's size, minus offset, must be at least calcsize(fmt).\n\
+See help(struct) for more on format strings.");
static PyObject *
unpack_from(PyObject *self, PyObject *args, PyObject *kwds)