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49 lines
1.9 KiB
C
49 lines
1.9 KiB
C
/* Determine whether the host has multiple processors. Linux version.
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Copyright (C) 1996, 2002 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include <sys/sysctl.h>
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/* Test whether the machine has more than one processor. This is not the
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best test but good enough. More complicated tests would require `malloc'
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which is not available at that time. */
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static inline int
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is_smp_system (void)
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{
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static const int sysctl_args[] = { CTL_KERN, KERN_VERSION };
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char buf[512];
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size_t reslen = sizeof (buf);
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/* Try reading the number using `sysctl' first. */
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if (__sysctl ((int *) sysctl_args,
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sizeof (sysctl_args) / sizeof (sysctl_args[0]),
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buf, &reslen, NULL, 0) < 0)
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{
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/* This was not successful. Now try reading the /proc filesystem. */
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int fd = __open ("/proc/sys/kernel/version", O_RDONLY);
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if (__builtin_expect (fd, 0) == -1
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|| (reslen = __read (fd, buf, sizeof (buf))) <= 0)
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/* This also didn't work. We give up and say it's a UP machine. */
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buf[0] = '\0';
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__close (fd);
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}
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return strstr (buf, "SMP") != NULL;
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}
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