diff options
author | Fred Drake <fdrake@acm.org> | 2001-08-01 16:50:49 (GMT) |
---|---|---|
committer | Fred Drake <fdrake@acm.org> | 2001-08-01 16:50:49 (GMT) |
commit | 630a63cafda87dbe46c5383e33773fe4032cf5b1 (patch) | |
tree | 2ef75ad7eb0ea96f418973508ef8c36dc42fcaa5 /Doc/lib | |
parent | 5a99e0ca0cf64240b8d02ec50c0374e19efb6ee4 (diff) | |
download | cpython-630a63cafda87dbe46c5383e33773fe4032cf5b1.zip cpython-630a63cafda87dbe46c5383e33773fe4032cf5b1.tar.gz cpython-630a63cafda87dbe46c5383e33773fe4032cf5b1.tar.bz2 |
Fix description of buffer_info(), and add a note that there is a better
way...
This closes SF bug #444842.
Diffstat (limited to 'Doc/lib')
-rw-r--r-- | Doc/lib/libarray.tex | 21 |
1 files changed, 15 insertions, 6 deletions
diff --git a/Doc/lib/libarray.tex b/Doc/lib/libarray.tex index bbbd90b..868770e 100644 --- a/Doc/lib/libarray.tex +++ b/Doc/lib/libarray.tex @@ -68,12 +68,21 @@ Append a new item with value \var{x} to the end of the array. \begin{methoddesc}[array]{buffer_info}{} Return a tuple \code{(\var{address}, \var{length})} giving the current -memory address and the length in bytes of the buffer used to hold -array's contents. This is occasionally useful when working with +memory address and the length in elements of the buffer used to hold +array's contents. The size of the memory buffer in bytes can be +computed as \code{\var{array}.buffer_info()[1] * +\var{array}.itemsize}. This is occasionally useful when working with low-level (and inherently unsafe) I/O interfaces that require memory -addresses, such as certain \cfunction{ioctl()} operations. The returned -numbers are valid as long as the array exists and no length-changing -operations are applied to it. +addresses, such as certain \cfunction{ioctl()} operations. The +returned numbers are valid as long as the array exists and no +length-changing operations are applied to it. + +\strong{Note:} When using array objects from code written in C or +\Cpp{} (the only way to effectively make use of this information), it +makes more sense to use the buffer interface supported by array +objects. This method is maintained for backward compatibility and +should be avoided in new code. The buffer interface is documented in +the \citetitle[../api/newTypes.html]{Python/C API Reference Manual}. \end{methoddesc} \begin{methoddesc}[array]{byteswap}{} @@ -174,7 +183,7 @@ string if the \var{typecode} is \code{'c'}, otherwise it is a list of numbers. The string is guaranteed to be able to be converted back to an array with the same type and value using reverse quotes (\code{``}), so long as the \function{array()} function has been -imported using \samp{from array import array}. Examples: +imported using \code{from array import array}. Examples: \begin{verbatim} array('l') |