From 0adfb45b9a2c892d4db211002b7c420790fa7e09 Mon Sep 17 00:00:00 2001 From: "Andrew M. Kuchling" Date: Sun, 18 Jun 2000 04:17:38 +0000 Subject: Make changes and clarifications suggested by Mark Hammond --- Doc/lib/libmmap.tex | 37 +++++++++++++++++++++++-------------- 1 file changed, 23 insertions(+), 14 deletions(-) diff --git a/Doc/lib/libmmap.tex b/Doc/lib/libmmap.tex index 5eccc7f..b88c348 100644 --- a/Doc/lib/libmmap.tex +++ b/Doc/lib/libmmap.tex @@ -19,17 +19,24 @@ different on Unix and on Windows. \begin{funcdesc}{mmap}{fileno, length \optional{, tagname} } (Windows version) Maps \var{length} bytes from the file specified by -the file handle \var{fileno}, and returns a mmap object. If you have -a Python file object, its -\method{fileno()} method returns the file's handle, which is just an integer. -\var{tagname}, if specified, is a string giving a tag name for the mapping. XXX what is the purpose of the tag name? +the file handle \var{fileno}, and returns a mmap object. If you wish +to map an existing Python file object, use its \method{fileno()} +method to obtain the correct value for the \var{fileno} parameter. + +\var{tagname}, if specified, is a string giving a tag name for the mapping. +Windows allows you to have many different mappings against the same +file. If you specify the name of an existing tag, that tag is opened, +otherwise a new tag of this name is created. If this parameter is +None, the mapping is created without a name. Avoiding the use of the +tag parameter will assist in keeping your code portable between Unix +and Windows. \end{funcdesc} -\begin{funcdesc}{mmap}{file, size \optional{, flags, prot}} +\begin{funcdesc}{mmap}{fileno, size \optional{, flags, prot}} (Unix version) Maps \var{length} bytes from the file specified by the -file handle \var{fileno}, and returns a mmap object. If you have a -Python file object, its \method{fileno()} method returns the file's -handle, which is just an integer. +file handle \var{fileno}, and returns a mmap object. If you wish to +map an existing Python file object, use its \method{fileno()} method +to obtain the correct value for the \var{fileno} parameter. \var{flags} specifies the nature of the mapping. \code{MAP_PRIVATE} creates a private copy-on-write mapping, so @@ -61,8 +68,10 @@ will result in an exception being raised. \begin{methoddesc}{flush}{\optional{\var{offset}, \var{size}}} Flushes changes made to the in-memory copy of a file back to disk. Without use of this call there is no guarantee that changes are -written back before the object is destroyed. If \var{offset} -and \var{size} are specified, only changes to the given range of bytes will be flushed to disk; otherwise, the whole extent of the mapping is flushed. +written back before the object is destroyed. If \var{offset} and +\var{size} are specified, only changes to the given range of bytes +will be flushed to disk; otherwise, the whole extent of the mapping is +flushed. \end{methoddesc} \begin{methoddesc}{move}{\var{dest}, \var{src}, \var{count}} @@ -71,14 +80,14 @@ to the destination index \var{dest}. \end{methoddesc} \begin{methoddesc}{read}{\var{num}} -Return a string containing up to \var{num} bytes taken from the +Return a string containing up to \var{num} bytes starting from the current file position; the file position is updated to point after the bytes that were returned. \end{methoddesc} \begin{methoddesc}{read_byte}{} -Returns the character at the current file position, and advancing -the file position by 1. +Returns a string of length 1 containing the character at the current +file position, and advances the file position by 1. \end{methoddesc} \begin{methoddesc}{readline}{} @@ -113,7 +122,7 @@ bytes that were written. \end{methoddesc} \begin{methoddesc}{write_byte}{\var{byte}} -Write \var{byte} into memory at the current position of +Write the single-character string \var{byte} into memory at the current position of the file pointer; the file position is advanced by 1. \end{methoddesc} -- cgit v0.12