cosmopolitan/libc/time/futimes.c

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net 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"

/**
 * Sets atime/mtime on file descriptor.
 *
 * @param ts is atime/mtime, or null for current time
 * @note better than microsecond precision on most platforms
 * @see fstat() for reading timestamps
 */
int futimes(int fd, const struct timeval tv[hasatleast 2]) {
  struct timespec ts[2];
  if (tv) {
    ts[0].tv_sec = tv[0].tv_sec;
    ts[0].tv_nsec = tv[0].tv_usec * 1000;
    ts[1].tv_sec = tv[1].tv_sec;
    ts[1].tv_nsec = tv[1].tv_usec * 1000;
    return utimensat(fd, NULL, ts, 0);
  } else {
    return utimensat(fd, NULL, NULL, 0);
  }
}