libc/stdio/__fsetlocking.c

   1 /* Copyright (C) 2004       Manuel Novoa III    <mjn3@codepoet.org>
   2  *
   3  * GNU Library General Public License (LGPL) version 2 or later.
   4  *
   5  * Dedicated to Toni.  See uClibc/DEDICATION.mjn3 for details.
   6  */
   7
   8 #include "_stdio.h"
   9 #include <stdio_ext.h>
  10
  11
  12 /* Not threadsafe. */
  13
  14 /* Notes:
  15  *   When setting the locking mode, glibc returns the previous setting.
  16  *   glibc treats invalid locking_mode args as FSETLOCKING_INTERNAL.
  17  */
  18
  19 int __fsetlocking(FILE *stream, int locking_mode)
  20 {
  21 #ifdef __UCLIBC_HAS_THREADS__
  22         int current = 1 + (stream->__user_locking & 1);
  23
  24         /* Check constant assumptions.  We can't test at build time
  25          * since these are enums. */
  26         assert((FSETLOCKING_QUERY == 0) && (FSETLOCKING_INTERNAL == 1)
  27                    && (FSETLOCKING_BYCALLER == 2));
  28
  29         __STDIO_STREAM_VALIDATE(stream);
  30         assert(((unsigned int) locking_mode) <= 2);
  31
  32         if (locking_mode != FSETLOCKING_QUERY) {
  33                 stream->__user_locking = ((locking_mode == FSETLOCKING_BYCALLER)
  34                                                                   ? 1
  35                                                                   : _stdio_user_locking); /* 0 or 2 */
  36                 __STDIO_STREAM_VALIDATE(stream);
  37         }
  38
  39         return current;
  40 #else
  41         __STDIO_STREAM_VALIDATE(stream);
  42         assert(((unsigned int) locking_mode) <= 2);
  43
  44         return FSETLOCKING_INTERNAL;
  45 #endif
  46 }
  47 libc_hidden_def(__fsetlocking)