newlib/libc/stdio/fsetlocking.c

   1 /*
   2  * Copyright (c) 2014 Red Hat, Inc.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  */
  26 /*
  27 FUNCTION
  28 <<__fsetlocking>>---set or query locking mode on FILE stream
  29
  30 INDEX
  31         __fsetlocking
  32
  33 SYNOPSIS
  34         #include <stdio.h>
  35         #include <stdio_ext.h>
  36         int __fsetlocking(FILE *<[fp]>, int <[type]>);
  37
  38 DESCRIPTION
  39 This function sets how the stdio functions handle locking of FILE <[fp]>.
  40 The following values describe <[type]>:
  41
  42 <<FSETLOCKING_INTERNAL>> is the default state, where stdio functions
  43 automatically lock and unlock the stream.
  44
  45 <<FSETLOCKING_BYCALLER>> means that automatic locking in stdio functions
  46 is disabled. Applications which set this take all responsibility for file
  47 locking themselves.
  48
  49 <<FSETLOCKING_QUERY>> returns the current locking mode without changing it.
  50
  51 RETURNS
  52 <<__fsetlocking>> returns the current locking mode of <[fp]>.
  53
  54 PORTABILITY
  55 This function originates from Solaris and is also provided by GNU libc.
  56
  57 No supporting OS subroutines are required.
  58 */
  59
  60 #ifndef __rtems__
  61
  62 #include <_ansi.h>
  63 #include <stdio.h>
  64 #include <stdio_ext.h>
  65 #include "local.h"
  66
  67 int
  68 __fsetlocking (FILE * fp,
  69        int type)
  70 {
  71   int result;
  72   CHECK_INIT(_REENT, fp);
  73   result = (fp->_flags2 & __SNLK) ? FSETLOCKING_BYCALLER : FSETLOCKING_INTERNAL;
  74   switch (type)
  75     {
  76     case FSETLOCKING_BYCALLER:
  77       fp->_flags2 |= __SNLK;
  78       break;
  79     case FSETLOCKING_INTERNAL:
  80       fp->_flags2 &= ~__SNLK;
  81       break;
  82     case FSETLOCKING_QUERY:
  83     default:
  84       break;
  85     }
  86   return result;
  87 }
  88
  89 #endif /* __rtems__ */