text: /* Implement fopen_unlocked and related functions.
     Copyright (C) 2005, 2011 Free Software Foundation, Inc.
     Written by Kaveh R. Ghazi <ghazi@caip.rutgers.edu>.
  
  This file is part of the libiberty library.
  Libiberty is free software; you can redistribute it and/or
  modify it under the terms of the GNU Library General Public
  License as published by the Free Software Foundation; either
  version 2 of the License, or (at your option) any later version.
  
  Libiberty 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
  Library General Public License for more details.
  
  You should have received a copy of the GNU Library General Public
  License along with libiberty; see the file COPYING.LIB.  If
  not, write to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
  Boston, MA 02110-1301, USA.  */
  
  /*
  
  @deftypefn Extension void unlock_stream (FILE * @var{stream})
  
  If the OS supports it, ensure that the supplied stream is setup to
  avoid any multi-threaded locking.  Otherwise leave the @code{FILE}
  pointer unchanged.  If the @var{stream} is @code{NULL} do nothing.
  
  @end deftypefn
  
  @deftypefn Extension void unlock_std_streams (void)
  
  If the OS supports it, ensure that the standard I/O streams,
  @code{stdin}, @code{stdout} and @code{stderr} are setup to avoid any
  multi-threaded locking.  Otherwise do nothing.
  
  @end deftypefn
  
  @deftypefn Extension {FILE *} fopen_unlocked (const char *@var{path}, @
    const char * @var{mode})
  
  Opens and returns a @code{FILE} pointer via @code{fopen}.  If the
  operating system supports it, ensure that the stream is setup to avoid
  any multi-threaded locking.  Otherwise return the @code{FILE} pointer
  unchanged.
  
  @end deftypefn
  
  @deftypefn Extension {FILE *} fdopen_unlocked (int @var{fildes}, @
    const char * @var{mode})
  
  Opens and returns a @code{FILE} pointer via @code{fdopen}.  If the
  operating system supports it, ensure that the stream is setup to avoid
  any multi-threaded locking.  Otherwise return the @code{FILE} pointer
  unchanged.
  
  @end deftypefn
  
  @deftypefn Extension {FILE *} freopen_unlocked (const char * @var{path}, @
    const char * @var{mode}, FILE * @var{stream})
  
  Opens and returns a @code{FILE} pointer via @code{freopen}.  If the
  operating system supports it, ensure that the stream is setup to avoid
  any multi-threaded locking.  Otherwise return the @code{FILE} pointer
  unchanged.
  
  @end deftypefn
  
  */
  
  #ifdef HAVE_CONFIG_H
  #include "config.h"
  #endif
  #include <stdio.h>
  #ifdef HAVE_STDIO_EXT_H
  #include <stdio_ext.h>
  #endif
  
  #include "libiberty.h"
  
  /* This is an inline helper function to consolidate attempts to unlock
     a stream.  */
  
  static inline void
  unlock_1 (FILE *const fp ATTRIBUTE_UNUSED)
  {
  #if defined(HAVE___FSETLOCKING) && defined(FSETLOCKING_BYCALLER)
    if (fp)
      __fsetlocking (fp, FSETLOCKING_BYCALLER);
  #endif
  }
  
  void
  unlock_stream (FILE *fp)
  {
    unlock_1 (fp);
  }
  
  void
  unlock_std_streams (void)
  {
    unlock_1 (stdin);
    unlock_1 (stdout);
    unlock_1 (stderr);
  }
  
  FILE *
  fopen_unlocked (const char *path, const char *mode)		
  {
    FILE *const fp = fopen (path, mode);
    unlock_1 (fp);
    return fp;
  }
  
  FILE *
  fdopen_unlocked (int fildes, const char *mode)
  {
    FILE *const fp = fdopen (fildes, mode);
    unlock_1 (fp);
    return fp;
  }
  
  FILE *
  freopen_unlocked (const char *path, const char *mode, FILE *stream)
  {
    FILE *const fp = freopen (path, mode, stream);
    unlock_1 (fp);
    return fp;
  }
  