Implement freading and fwriting.

* lib/freading.c: New file.
* lib/freading.h: Likewise.
* m4/freading.m4: Likewise.
* modules/freading: Likewise.
* modules/freading-tests: Likewise.
* tests/test-freading.c: Likewise.
* lib/fwriting.c: New file.
* lib/fwriting.h: Likewise.
* m4/fwriting.m4: Likewise.
* modules/fwriting: Likewise.
* modules/fwriting-tests: Likewise.
* tests/test-fwriting.c: Likewise.
* MODULES.html.sh (File stream based Input/Output): Mention them.

1 files changed, 38 insertions, 0 deletions

diff --git a/lib/fwriting.c b/lib/fwriting.c
new file mode 100644
index 0000000000..302053733a
--- /dev/null
+++ b/lib/fwriting.c
@@ -0,0 +1,38 @@
+/* Retrieve information about a FILE stream.
+   Copyright (C) 2007 Free Software Foundation, Inc.
+
+   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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
+
+#include <config.h>
+
+/* Specification.  */
+#include "fwriting.h"
+
+bool
+fwriting (FILE *fp)
+{
+  /* Most systems provide FILE as a struct and the necessary bitmask in
+     <stdio.h>, because they need it for implementing getc() and putc() as
+     fast macros.  */
+#if defined _IO_ferror_unlocked     /* GNU libc, BeOS */
+  return (fp->_flags & (_IO_NO_READS | _IO_CURRENTLY_PUTTING)) != 0;
+#elif defined __sferror             /* FreeBSD, NetBSD, OpenBSD, MacOS X, Cygwin */
+  return (fp->_flags & __SWR) != 0;
+#elif defined _IOERR                /* AIX, HP-UX, IRIX, OSF/1, Solaris, mingw */
+  return (fp->_flag & _IOWRT) != 0;
+#else
+ #error "Please port gnulib fwriting.c to your platform!"
+#endif
+}