getpid.c 2.0 KB

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  1. /* Copyright (C) 2003, 2004 Free Software Foundation, Inc.
  2. This file is part of the GNU C Library.
  3. Contributed by Ulrich Drepper <drepper@redhat.com>, 2003.
  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 <unistd.h>
  17. #include <tls.h>
  18. #include <sysdep.h>
  19. #ifndef NOT_IN_libc
  20. static inline __attribute__((always_inline)) pid_t really_getpid (pid_t oldval);
  21. static inline __attribute__((always_inline)) pid_t
  22. really_getpid (pid_t oldval)
  23. {
  24. if (__builtin_expect (oldval == 0, 1))
  25. {
  26. pid_t selftid = THREAD_GETMEM (THREAD_SELF, tid);
  27. if (__builtin_expect (selftid != 0, 1))
  28. return selftid;
  29. }
  30. INTERNAL_SYSCALL_DECL (err);
  31. pid_t result = INTERNAL_SYSCALL (getpid, err, 0);
  32. /* We do not set the PID field in the TID here since we might be
  33. called from a signal handler while the thread executes fork. */
  34. if (oldval == 0)
  35. THREAD_SETMEM (THREAD_SELF, tid, result);
  36. return result;
  37. }
  38. #endif
  39. extern __typeof(getpid) __getpid;
  40. pid_t
  41. __getpid (void)
  42. {
  43. #ifdef NOT_IN_libc
  44. INTERNAL_SYSCALL_DECL (err);
  45. pid_t result = INTERNAL_SYSCALL (getpid, err, 0);
  46. #else
  47. pid_t result = THREAD_GETMEM (THREAD_SELF, pid);
  48. if (__builtin_expect (result <= 0, 0))
  49. result = really_getpid (result);
  50. #endif
  51. return result;
  52. }
  53. libc_hidden_proto(getpid)
  54. weak_alias(__getpid, getpid)
  55. libc_hidden_weak(getpid)