73 lines
2.6 KiB
C
73 lines
2.6 KiB
C
/* $OpenBSD: time.c,v 1.5 2005/08/08 08:05:34 espie Exp $ */
|
|
/*
|
|
* Copyright (c) 1983, 1993
|
|
* The Regents of the University of California. All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
* 3. Neither the name of the University nor the names of its contributors
|
|
* may be used to endorse or promote products derived from this software
|
|
* without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
* SUCH DAMAGE.
|
|
*/
|
|
|
|
#include <time.h>
|
|
|
|
time_t
|
|
time(time_t *t)
|
|
{
|
|
struct timeval tt;
|
|
time_t ret;
|
|
|
|
if (gettimeofday(&tt, (struct timezone *)0) < 0)
|
|
ret = -1;
|
|
else
|
|
ret = tt.tv_sec;
|
|
if (t != NULL)
|
|
*t = ret;
|
|
return ret;
|
|
}
|
|
|
|
// return monotonically increasing CPU time in ticks relative to unspecified epoch
|
|
static inline clock_t clock_now(void)
|
|
{
|
|
struct timespec tm;
|
|
clock_gettime( CLOCK_MONOTONIC, &tm);
|
|
return tm.tv_sec * CLOCKS_PER_SEC + (tm.tv_nsec * (CLOCKS_PER_SEC/1e9));
|
|
}
|
|
|
|
// initialized by the constructor below
|
|
static clock_t clock_start;
|
|
|
|
// called by dlopen when .so is loaded
|
|
__attribute__((constructor)) static void clock_crt0(void)
|
|
{
|
|
clock_start = clock_now();
|
|
}
|
|
|
|
// return elapsed CPU time in clock ticks, since start of program execution
|
|
// (spec says epoch is undefined, but glibc uses crt0 as epoch)
|
|
clock_t
|
|
clock(void)
|
|
{
|
|
// note that if we are executing in a different thread than crt0, then the
|
|
// pthread_create that made us had a memory barrier so clock_start is defined
|
|
return clock_now() - clock_start;
|
|
}
|