time(3)

time3

Get time of day

Usage

#include <time.h>

time_t

time(time_t *tloc);

Library

Standard C Library (libc, -lc)

Overview

The time() function returns the value of time in seconds since 0 hours, 0 minutes, 0 seconds, January 1, 1970, Coordinated Universal Time, without including leap seconds. If an error occurs, time() returns the value (time_t)-1.

The return value is also stored in *tloc, provided that tloc is non-null.

Errors

The time() function may fail for any of the reasons described in gettimeofday(2).

Releases

163 releases since Mac OS X 10.0; the text changed 4 times.

  1. 10.0–10.1.5
  2. 10.2–10.3.9
  3. 10.4–10.4.11
  4. 10.5–10.6.8
  5. 10.7–26.5

Standards

The time function conforms to IEEE Std 1003.1-2001 (“POSIX.1”).

History

A time() function appeared in Version 6 AT&T UNIX.

Bugs

Neither ISO/IEC 9899:1999 (“ISO C99”) nor IEEE Std 1003.1-2001 (“POSIX.1”) requires time() to set errno on failure; thus, it is impossible for an application to distinguish the valid time value -1 (representing the last UTC second of 1969) from the error return value.

Systems conforming to earlier versions of the C and POSIX standards (including older versions of FreeBSD) did not set *tloc in the error case.

From Libc 1752.120.2 in macOS 26.5. Parsed by carta from the page's mdoc source.