X-Git-Url: https://code.delx.au/gnu-emacs/blobdiff_plain/2dbd7a37a809e2dcef6c8e7323ac15c98b051cd9..f15c8583198c3d6c26ca0c0a5b6fb019f98d6c3c:/doc/lispref/streams.texi

diff --git a/doc/lispref/streams.texi b/doc/lispref/streams.texi
index c287b61771..e52a543110 100644
--- a/doc/lispref/streams.texi
+++ b/doc/lispref/streams.texi
@@ -1,6 +1,6 @@
 @c -*-texinfo-*-
 @c This is part of the GNU Emacs Lisp Reference Manual.
-@c Copyright (C) 1990-1994, 1998-1999, 2001-2014 Free Software
+@c Copyright (C) 1990-1994, 1998-1999, 2001-2015 Free Software
 @c Foundation, Inc.
 @c See the file elisp.texi for copying conditions.
 @node Read and Print
@@ -339,6 +339,25 @@ shared structures.  @xref{Circular Objects}.  Its default value is
 @code{t}.
 @end defvar
 
+@cindex binary I/O in batch mode
+When reading or writing from the standard input/output streams of the
+Emacs process in batch mode, it is sometimes required to make sure any
+arbitrary binary data will be read/written verbatim, and/or that no
+translation of newlines to or from CR-LF pairs are performed.  This
+issue does not exist on Posix hosts, only on MS-Windows and MS-DOS.
+The following function allows to control the I/O mode of any standard
+stream of the Emacs process.
+
+@defun set-binary-mode stream mode
+Switch @var{stream} into binary or text I/O mode.  If @var{mode} is
+non-@code{nil}, switch to binary mode, otherwise switch to text mode.
+The value of @var{stream} can be one of @code{stdin}, @code{stdout},
+or @code{stderr}.  This function flushes any pending output data of
+@var{stream} as a side effect, and returns the previous value of I/O
+mode for @var{stream}.  On Posix hosts, it always returns a
+non-@code{nil} value and does nothing except flushing pending output.
+@end defun
+
 @node Output Streams
 @section Output Streams
 @cindex stream (for printing)
@@ -618,7 +637,7 @@ spacing between calls.
 @defun terpri &optional stream ensure
 @cindex newline in print
 This function outputs a newline to @var{stream}.  The name stands for
-``terminate print''.  If @var{ensure} is non-nil no newline is printed
+``terminate print''.  If @var{ensure} is non-@code{nil} no newline is printed
 if @var{stream} is already at the beginning of a line.  Note in this
 case @var{stream} can not be a function and an error is signalled if
 it is.  This function returns @code{t} if a newline is printed.
@@ -686,6 +705,11 @@ This function outputs @var{object} to @var{stream}, just like
 indent and fill the object to make it more readable for humans.
 @end defun
 
+If you need to use binary I/O in batch mode, e.g., use the functions
+described in this section to write out arbitrary binary data or avoid
+conversion of newlines on non-Posix hosts, see @ref{Input Functions,
+set-binary-mode}.
+
 @node Output Variables
 @section Variables Affecting Output
 @cindex output-controlling variables