< c‎ | chrono
Defined in header <time.h>
typedef /* unspecified */ time_t;

Arithmetic (until C11) Real (since C11) type capable of representing times.

Although not defined by the C standard, this is almost always an integral value holding the number of seconds (not counting leap seconds) since 00:00, Jan 1 1970 UTC, corresponding to POSIX time.


[edit] Notes

The standard uses the term calendar time when referring to a value of type time_t.

[edit] Example

Show the start of the epoch.

#include <stdio.h>
#include <time.h>
int main(void)
    time_t epoch = 0;
    printf("%ld seconds since the epoch began\n", (long)epoch);
    printf("%s", asctime(gmtime(&epoch)));

Possible output:

0 seconds since the epoch began
Thu Jan  1 00:00:00 1970

[edit] References

  • C11 standard (ISO/IEC 9899:2011):
  • 7.27.1/3 Components of time (p: 388)
  • C99 standard (ISO/IEC 9899:1999):
  • 7.23.1/3 Components of time (p: 338)
  • C89/C90 standard (ISO/IEC 9899:1990):

[edit] See also

returns the current calendar time of the system as time since epoch
(function) [edit]
converts time since epoch to calendar time expressed as local time
(function) [edit]
converts time since epoch to calendar time expressed as Coordinated Universal Time (UTC)
(function) [edit]