time_t

 

C

Language

Standard Library

Type support

Dynamic memory management

Error handling

Program utilities

Date and time utilities

Strings library

Algorithms

Numerics

Input/output support

Localization support

Thread support (C11)

Atomic operations (C11)

 

Date and time utilities

Functions

Time manipulation

difftime

time

clock

timespec_get (C11)

Format conversions

asctime

ctime

strftime

wcsftime

gmtime

localtime

mktime

Constants

CLOCKS_PER_SEC

Types

tm

time_t

clock_t

timespec (C11)

 

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

Arithmetic type capable of representing times.

Although not defined, 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.

Example

Show the start of the epoch.

Run this code

#include <stdio.h>
#include <time.h>
 
int main(void)
{
    time_t epoch = 0;
    printf("%d seconds since the epoch began\n", (int)epoch);
    printf("%s\n", asctime(localtime(&epoch)));
 
    return 0;
}

Possible output:

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

See also

time	returns the current calendar time of the system as time since epoch (function)
localtime	converts time since epoch to calendar time expressed as local time (function)
gmtime	converts time since epoch to calendar time expressed as Coordinated Universal Time (UTC) (function)
C++ documentation for time_t