new module 'fpurge'

[Bruno Haible]

This generalizes the fpurge() function from the BSDs (FreeBSD, MacOS X,
OpenBSD, NetBSD).

2007-04-13  Bruno Haible  <address@hidden>

        * modules/fpurge: New file.
        * lib/fpurge.h: New file.
        * lib/fpurge.c: New file.
        * m4/fpurge.m4: New file.

============================ modules/fpurge ==============================
Description:
fpurge() function: Flush buffers.

Files:
lib/fpurge.h
lib/fpurge.c
m4/fpurge.m4

Depends-on:

configure.ac:
gl_FUNC_FPURGE

Makefile.am:

Include:
"fpurge.h"

License:
LGPL

Maintainer:
Bruno Haible, Eric Blake

============================= lib/fpurge.h ===============================
/* Flushing buffers of 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 <stdio.h>

/* Discard all pending buffered I/O on the stream STREAM.
   STREAM must not be wide-character oriented.
   Return 0 if successful.  Upon error, return -1 and set errno.  */

#if HAVE___FPURGE /* glibc >= 2.2, Solaris >= 7 */

# include <stdio_ext.h>
# define fpurge(stream) (__fpurge (stream), 0)

#elif ! HAVE_DECL_FPURGE

# ifdef __cplusplus
extern "C" {
# endif

extern int fpurge (FILE *stream);

# ifdef __cplusplus
}
# endif

#endif
============================= lib/fpurge.c ===============================
/* Flushing buffers of 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 "fpurge.h"

int
fpurge (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 */
  fp->_IO_read_end = fp->_IO_read_ptr;
  fp->_IO_write_ptr = fp->_IO_write_base;
  return 0;
#elif defined __sferror             /* FreeBSD, NetBSD, OpenBSD, MacOS X, 
Cygwin */
  fp->_p = fp->_bf._base;
  fp->_r = 0;
  fp->_w = ((fp->_flags & (__SLBF | __SNBF) == 0) /* fully buffered? */
            ? fp->_bf._size
            : 0);
#elif defined _IOERR                /* AIX, HP-UX, IRIX, OSF/1, Solaris, mingw 
*/
  fp->_ptr = fp->_base;
  if (fp->_ptr != NULL)
    fp->_cnt = 0;
  return 0;
#else
 #error "Please port gnulib fpurge.c to your platform!"
#endif
}
============================= m4/fpurge.m4 ===============================
# fpurge.m4 serial 1
dnl Copyright (C) 2007 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.

AC_DEFUN([gl_FUNC_FPURGE],
[
  AC_CHECK_FUNCS_ONCE([fpurge])
  AC_CHECK_FUNCS_ONCE([__fpurge])
  AC_CHECK_DECLS([fpurge], , , [#include <stdio.h>])
  if test $ac_cv_func_fpurge = no && test $ac_cv_func___fpurge = no; then
    AC_LIBOBJ([fpurge])
    AC_CHECK_FUNCS([fpurge])
  fi
])