pmt: initial 3.0.2 update

include/libgnulib/fwriteerror.h

@@ -0,0 +1,62 @@
+/* Detect write error on a stream.
+   Copyright (C) 2003, 2005-2006, 2009-2024 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 3 of the License, 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, see <https://www.gnu.org/licenses/>.  */
+
+/* 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
+         the return value of the final fclose() call.
+
+   The benefit of (a) is that non file related errors (such that ENOMEM during
+   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
+   users can easily figure out by themselves why a file cannot be written to,
+   and furthermore the function fwriteerror() can provide errno as well.
+
+   The big drawback of (a) is extensive error checking code: Every function
+   which does stream output must return an error indicator.
+
+   This file provides support for (b).  */
+
+#include <stdio.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Write out the not yet written buffered contents of the stream FP, close
+   the stream FP, and test whether some error occurred on the stream FP.
+   FP must be a stream opened for writing.
+   Return 0 if no error occurred and fclose (fp) succeeded.
+   Return -1 and set errno if there was an error.  The errno value will be 0
+   if the cause of the error cannot be determined.
+   For any given stream FP other than stdout, fwriteerror (FP) may only be
+   called once.  */
+extern int fwriteerror (FILE *fp);
+
+/* Likewise, but don't consider it an error if FP has an invalid file
+   descriptor and no output was done to FP.  */
+extern int fwriteerror_no_ebadf (FILE *fp);
+
+#ifdef __cplusplus
+}
+#endif