Added documentation for TemporaryFile() and the siffix parameter to mktemp().

Removed obsolete comments about this module not creating or removing actual
files.
Removed obsolete comment about users needing to set template to None after
calling os.fork().

Doc/lib/libtempfile.tex

@@ -11,15 +11,35 @@
 This module generates temporary file names.  It is not \UNIX{} specific,
 but it may require some help on non-\UNIX{} systems.
 
-Note: the modules does not create temporary files, nor does it
-automatically remove them when the current process exits or dies.
+The module defines the following user-callable functions:
 
-The module defines a single user-callable function:
-
-\begin{funcdesc}{mktemp}{}
+\begin{funcdesc}{mktemp}{\optional{suffix}}
 Return a unique temporary filename.  This is an absolute pathname of a
 file that does not exist at the time the call is made.  No two calls
-will return the same filename.
+will return the same filename.  \var{suffix}, if provided, is used as
+the last part of the generated file name.  This can be used to provide
+a filename extension or other identifying information that may be
+useful on some platforms.
+\end{funcdesc}
+
+\begin{funcdesc}{TemporaryFile}{\optional{mode\optional{,
+                                bufsize\optional{, suffix}}}}
+Return a file (or file-like) object that can be used as a temporary
+storage area.  The file is created in the most secure manner available
+in the appporpriate temporary directory for the host platform.  Under
+\UNIX, the directory entry to the file is removed so that it is secure
+against attacks which involve creating symbolic links to the file or
+replacing the file with a symbolic link to some other file.  For other
+platforms, which don't allow removing the directory entry while the
+file is in use, the file is automatically deleted as soon as it is
+closed (including an implicit close when it is garbage-collected).
+
+The \var{mode} parameter defaults to \code{'w+b'} so that the file
+created can be read and written without being closed.  Binary mode is
+used so that it behaves consistently on all platforms without regard
+for the data that is stored.  \var{bufsize} defaults to \code{-1},
+meaning that the operating system default is used.  \var{suffix} is
+passed to \function{mktemp()}.
 \end{funcdesc}
 
 The module uses two global variables that tell it how to construct a
@@ -43,10 +63,3 @@ unique filenames.  The default is either \file{@\var{pid}.} where
 \var{pid} is the current process ID (on \UNIX{}), or \file{tmp} (all
 other systems).
 \end{datadesc}
-
-\strong{Warning:} if a \UNIX{} process uses \code{mktemp()}, then
-calls \function{fork()} and both parent and child continue to use
-\function{mktemp()}, the processes will generate conflicting temporary
-names.  To resolve this, the child process should assign \code{None} to
-\code{template}, to force recomputing the default on the next call
-to \function{mktemp()}.