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.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Library General Public License as
7 published by the Free Software Foundation; either version 2 of the
8 License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Library General Public License for more details.
15 You should have received a copy of the GNU Library General Public
16 License along with the GNU C Library; see the file COPYING.LIB. If not,
17 see <http://www.gnu.org/licenses/>. */
19 #include <sys/sysctl.h>
21 /* Test whether the machine has more than one processor. This is not the
22 best test but good enough. More complicated tests would require `malloc'
23 which is not available at that time. */
27 static const int sysctl_args[] = { CTL_KERN, KERN_VERSION };
29 size_t reslen = sizeof (buf);
31 /* Try reading the number using `sysctl' first. */
32 if (__sysctl ((int *) sysctl_args,
33 sizeof (sysctl_args) / sizeof (sysctl_args[0]),
34 buf, &reslen, NULL, 0) < 0)
36 /* This was not successful. Now try reading the /proc filesystem. */
37 int fd = __open ("/proc/sys/kernel/version", O_RDONLY);
38 if (__builtin_expect (fd, 0) == -1
39 || (reslen = __read (fd, buf, sizeof (buf))) <= 0)
40 /* This also didn't work. We give up and say it's a UP machine. */
46 return strstr (buf, "SMP") != NULL;