pthread_once.c 1.6 KB

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  1. /* Copyright (C) 2002, 2007 Free Software Foundation, Inc.
  2. This file is part of the GNU C Library.
  3. Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
  4. The GNU C Library is free software; you can redistribute it and/or
  5. modify it under the terms of the GNU Lesser General Public
  6. License as published by the Free Software Foundation; either
  7. version 2.1 of the License, or (at your option) any later version.
  8. The GNU C Library is distributed in the hope that it will be useful,
  9. but WITHOUT ANY WARRANTY; without even the implied warranty of
  10. MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  11. Lesser General Public License for more details.
  12. You should have received a copy of the GNU Lesser General Public
  13. License along with the GNU C Library; if not, write to the Free
  14. Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  15. 02111-1307 USA. */
  16. #include "pthreadP.h"
  17. #include <lowlevellock.h>
  18. static int once_lock = LLL_LOCK_INITIALIZER;
  19. int
  20. __pthread_once (
  21. pthread_once_t *once_control,
  22. void (*init_routine) (void))
  23. {
  24. /* XXX Depending on whether the LOCK_IN_ONCE_T is defined use a
  25. global lock variable or one which is part of the pthread_once_t
  26. object. */
  27. if (*once_control == PTHREAD_ONCE_INIT)
  28. {
  29. lll_lock (once_lock, LLL_PRIVATE);
  30. /* XXX This implementation is not complete. It doesn't take
  31. cancelation and fork into account. */
  32. if (*once_control == PTHREAD_ONCE_INIT)
  33. {
  34. init_routine ();
  35. *once_control = !PTHREAD_ONCE_INIT;
  36. }
  37. lll_unlock (once_lock, LLL_PRIVATE);
  38. }
  39. return 0;
  40. }
  41. strong_alias (__pthread_once, pthread_once)