cosmopolitan/libc/calls/gettimeofday.c
Justine Tunney b0df6c1fce
Implement proper time zone support
Cosmopolitan now supports 104 time zones. They're embedded inside any
binary that links the localtime() function. Doing so adds about 100kb
to the binary size. This change also gets time zones working properly
on Windows for the first time. It's not needed to have /etc/localtime
exist on Windows, since we can get this information from WIN32. We're
also now updated to the latest version of Paul Eggert's TZ library.
2024-05-04 23:06:37 -07:00

60 lines
2.8 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi │
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/calls/struct/timespec.h"
#include "libc/calls/struct/timeval.h"
#include "libc/sysv/consts/clock.h"
#include "libc/time.h"
/**
* Returns system wall time in microseconds, e.g.
*
* int64_t t;
* char p[20];
* struct tm tm;
* struct timeval tv;
* gettimeofday(&tv, 0);
* t = tv.tv_sec;
* gmtime_r(&t, &tm);
* iso8601(p, &tm);
* printf("%s\n", p);
*
* @param tv points to timeval that receives result if non-null
* @param tz is completely ignored
* @return 0 on success, or -1 w/ errno
* @raise EFAULT if `tv` points to invalid memory
* @see clock_gettime() for nanosecond precision
* @see strftime() for string formatting
* @asyncsignalsafe
* @vforksafe
*/
int gettimeofday(struct timeval *tv, struct timezone *tz) {
if (tv) {
struct timespec ts;
if (clock_gettime(CLOCK_REALTIME, &ts) != -1) {
tv->tv_sec = ts.tv_sec;
tv->tv_usec = (ts.tv_nsec + 999) / 1000;
return 0;
} else {
return -1;
}
} else {
return 0;
}
}