+
−/* Detect write error on a stream.
+
−   Copyright (C) 2003 Free Software Foundation, Inc.
+
−   Written by Bruno Haible <bruno@clisp.org>, 2003.
+
−
+
−   This program is free software; you can redistribute it and/or modify
+
−   it under the terms of the GNU General Public License as published by
+
−   the Free Software Foundation; either version 2, or (at your option)
+
−   any later version.
+
−
+
−   This program is distributed in the hope that it will be useful,
+
−   but WITHOUT ANY WARRANTY; without even the implied warranty of
+
−   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+
−   GNU General Public License for more details.
+
−
+
−   You should have received a copy of the GNU General Public License
+
−   along with this program; if not, write to the Free Software Foundation,
+
−   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
+
−
+
−/* There are two approaches for detecting a write error on a stream opened
+
−   for writing:
+
−
+
−     (a) Test the return value of every fwrite() or fprintf() call, and react
+
−         immediately.
+
−     (b) Just before fclose(), test the error indicator in the stream and
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−         the return value of the final fflush() or fclose() call.
+
−
+
−   The benefit of (a) is that non file related errors (such that ENOMEM during
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−   fprintf) and temporary error conditions can be diagnosed accurately.
+
−
+
−   A theoretical benefit of (a) is also that, on POSIX systems, in the case of
+
−   an ENOSPC error, errno is set and can be used by error() to provide a more
+
−   accurate error message. But in practice, this benefit is not big because
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−   users can easily figure out by themselves why a file cannot be written to,
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−   and furthermore the function fwriteerror() can provide errno as well.
+
−
+
−   The big drawback of (a) is extensive error checking code: Every function
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−   which does stream output must return an error indicator.
+
−
+
−   This file provides support for (b).  */
+
−
+
−#include <stdio.h>
+
−
+
−/* Write out the not yet written buffered contents of the stream FP, and then
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−   test whether some error occurred on the stream FP.  FP must be a stream
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−   opened for writing.
+
−   Return 0 if no error occurred.  In this case it can be assumed that
+
−   fclose (fp) will succeed.
+
−   Return -1 and set errno if there was an error.  The errno value will be 0
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−   if the cause of the error cannot be determined.
+
− */
+
−extern int fwriteerror (FILE *fp);