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git.ipfire.org Git - thirdparty/glibc.git/blob - sysdeps/unix/sysv/linux/i386/smp.h
1 /* Determine whether the host has multiple processors. Linux version.
2 Copyright (C) 1996-2020 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
17 not, see <https://www.gnu.org/licenses/>. */
22 #include <sys/utsname.h>
23 #include <not-cancel.h>
25 /* Test whether the machine has more than one processor. This is not the
26 best test but good enough. More complicated tests would require `malloc'
27 which is not available at that time. */
38 /* Try reading the number using `sysctl' first. */
39 if (__uname (&u
.uts
) == 0)
43 /* This was not successful. Now try reading the /proc filesystem. */
44 int fd
= __open64_nocancel ("/proc/sys/kernel/version", O_RDONLY
);
45 if (__builtin_expect (fd
, 0) == -1
46 || __read_nocancel (fd
, u
.buf
, sizeof (u
.buf
)) <= 0)
47 /* This also didn't work. We give up and say it's a UP machine. */
50 __close_nocancel_nostatus (fd
);
54 return strstr (cp
, "SMP") != NULL
;