lib/call_once.c

   1 /* ISO C 11 once-only initialization.
   2    Copyright (C) 2005-2024 Free Software Foundation, Inc.
   3
   4    This file is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU Lesser General Public License as
   6    published by the Free Software Foundation; either version 2.1 of the
   7    License, or (at your option) any later version.
   8
   9    This file is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 /* Written by Bruno Haible <bruno@clisp.org>, 2005, 2019.
  18    Based on GCC's gthr-posix.h, gthr-posix95.h, gthr-win32.h.  */
  19
  20 #include <config.h>
  21
  22 #include <threads.h>
  23
  24 #include <errno.h>
  25
  26 #if defined _WIN32 && ! defined __CYGWIN__
  27 /* Use Windows threads.  */
  28
  29 # define WIN32_LEAN_AND_MEAN  /* avoid including junk */
  30 # include <windows.h>
  31
  32 # include <stdlib.h>
  33
  34 #else
  35 /* Use POSIX threads.  */
  36
  37 # include <pthread.h>
  38
  39 #endif
  40
  41 #if defined _WIN32 && ! defined __CYGWIN__
  42 /* Use Windows threads.  */
  43
  44 void
  45 call_once (once_flag *flagp, void (*func) (void))
  46 {
  47   glwthread_once (flagp, func);
  48 }
  49
  50 #else
  51 /* Use POSIX threads.  */
  52
  53 void
  54 call_once (once_flag *flagp, void (*func) (void))
  55 {
  56 # if defined __CYGWIN__
  57   /* Verify that once_flag and pthread_once_t are of the same size.  */
  58   struct _ { int v [sizeof (once_flag) == sizeof (pthread_once_t) ? 1 : -1]; };
  59   pthread_once ((pthread_once_t *) flagp, func);
  60 # else
  61   pthread_once (flagp, func);
  62 # endif
  63 }
  64
  65 #endif