TIME(3) BSD Library Functions Manual TIME(3)NAMEtime — get time of day
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <time.h>
time_t
time(time_t *tloc);
DESCRIPTION
The time() 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 ALSOgettimeofday(2), ctime(3)STANDARDS
The time() function conforms to ISO/IEC 9945-1:1990 (“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.
BSD November 5, 2011 BSD
