smp.h 1.9 KB

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  1. /* Determine whether the host has multiple processors. Linux version.
  2. Copyright (C) 1996, 2002 Free Software Foundation, Inc.
  3. This file is part of the GNU C Library.
  4. The GNU C Library is free software; you can redistribute it and/or
  5. modify it under the terms of the GNU Library General Public License as
  6. published by the Free Software Foundation; either version 2 of the
  7. 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. Library General Public License for more details.
  12. You should have received a copy of the GNU Library General Public
  13. License along with the GNU C Library; see the file COPYING.LIB. If not,
  14. write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  15. Boston, MA 02111-1307, USA. */
  16. #include <sys/sysctl.h>
  17. /* Test whether the machine has more than one processor. This is not the
  18. best test but good enough. More complicated tests would require `malloc'
  19. which is not available at that time. */
  20. static __inline__ int
  21. is_smp_system (void)
  22. {
  23. static const int sysctl_args[] = { CTL_KERN, KERN_VERSION };
  24. char buf[512];
  25. size_t reslen = sizeof (buf);
  26. /* Try reading the number using `sysctl' first. */
  27. if (__sysctl ((int *) sysctl_args,
  28. sizeof (sysctl_args) / sizeof (sysctl_args[0]),
  29. buf, &reslen, NULL, 0) < 0)
  30. {
  31. /* This was not successful. Now try reading the /proc filesystem. */
  32. int fd = __open ("/proc/sys/kernel/version", O_RDONLY);
  33. if (__builtin_expect (fd, 0) == -1
  34. || (reslen = __read (fd, buf, sizeof (buf))) <= 0)
  35. /* This also didn't work. We give up and say it's a UP machine. */
  36. buf[0] = '\0';
  37. __close (fd);
  38. }
  39. return strstr (buf, "SMP") != NULL;
  40. }