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Fix description of buffer_info(), and add a note that there is a better 

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This closes SF bug #444842.
This commit is contained in:
Fred Drake 2001-08-01 16:50:49 +00:00
parent 5a99e0ca0c
commit 630a63cafd
1 changed files with 15 additions and 6 deletions
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21
Doc/lib/libarray.tex
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@ -68,12 +68,21 @@ Append a new item with value \var{x} to the end of the array.
\begin{methoddesc}[array]{buffer_info}{} \begin{methoddesc}[array]{buffer_info}{}
Return a tuple \code{(\var{address}, \var{length})} giving the current Return a tuple \code{(\var{address}, \var{length})} giving the current
memory address and the length in bytes of the buffer used to hold memory address and the length in elements of the buffer used to hold
array's contents. This is occasionally useful when working with 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 low-level (and inherently unsafe) I/O interfaces that require memory
addresses, such as certain \cfunction{ioctl()} operations. The returned addresses, such as certain \cfunction{ioctl()} operations. The
numbers are valid as long as the array exists and no length-changing returned numbers are valid as long as the array exists and no
operations are applied to it. 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} \end{methoddesc}
\begin{methoddesc}[array]{byteswap}{} \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 numbers. The string is guaranteed to be able to be converted back to
an array with the same type and value using reverse quotes an array with the same type and value using reverse quotes
(\code{``}), so long as the \function{array()} function has been (\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} \begin{verbatim}
array('l') array('l')