NAME
time —
get time of day
LIBRARY
library “libc”
SYNOPSIS
#include
<time.h>
time_t
time(time_t
*tloc);
DESCRIPTION
Thetime()
function returns the value of time in seconds since 0 hours, 0 minutes, 0
seconds, January 1, 1970, Coordinated Universal Time.
A copy of the time value may be saved to the area indicated by the
pointer tloc. If tloc is a
NULL pointer, no value is stored.
Upon successful completion,
time()
returns the value of time. Otherwise a value of
((time_t) -1) is returned and the global variable
errno is set to indicate the error.
ERRORS
No errors are defined.
SEE ALSO
STANDARDS
The time() function conforms to
IEEE Std 1003.1-1990 (“POSIX.1”).
HISTORY
A time() function appeared in
Version 2 AT&T UNIX. It returned a 32-bit
value measuring sixtieths of a second, leading to rollover every 2.26 years.
In Version 6 AT&T UNIX, the precision of
time() was changed to seconds, allowing 135.6 years
between rollovers.
In NetBSD 6.0 the time_t type was changed to be 64 bits wide, including on 32-bit machines, making rollover a concern for the far distant future only. Note however that any code making the incorrect assumption that time_t is the same as long will fail on 32-bit machines in 2038.