glibc/sysdeps/unix/sysv/linux/clock.c
Andreas Jaeger 41bdb6e20c Update to LGPL v2.1.
2001-07-06  Paul Eggert  <eggert@twinsun.com>

	* manual/argp.texi: Remove ignored LGPL copyright notice; it's
	not appropriate for documentation anyway.
	* manual/libc-texinfo.sh: "Library General Public License" ->
	"Lesser General Public License".

2001-07-06  Andreas Jaeger  <aj@suse.de>

	* All files under GPL/LGPL version 2: Place under LGPL version
	2.1.
2001-07-06 04:58:11 +00:00

46 lines
1.8 KiB
C

/* Copyright (C) 1991, 1992, 1996, 1999 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <sys/times.h>
#include <time.h>
#include <unistd.h>
/* Return the time used by the program so far (user time + system time). */
clock_t
clock (void)
{
struct tms buf;
long clk_tck = __sysconf (_SC_CLK_TCK);
/* We don't check for errors here. The only error the kernel
returns is EFAULT if the value cannot be written to the struct we
pass a pointer to. Otherwise the kernel returns an `unsigned
long' value which is the number of jiffies since system start.
But this number can be negative (when read as `long') when the
system is up for some time. Ignoring errors should therefore
have no negative impacts but solve the problem. */
__times (&buf);
return
(clk_tck <= CLOCKS_PER_SEC)
? ((unsigned long) buf.tms_utime + buf.tms_stime) * (CLOCKS_PER_SEC
/ clk_tck)
: ((unsigned long) buf.tms_utime + buf.tms_stime) / (clk_tck
/ CLOCKS_PER_SEC);
}