gettimeofday(2) gettimeofday(2)
NAME [Toc] [Back]
gettimeofday - get the date and time
SYNOPSIS [Toc] [Back]
#include <sys/time.h>
int gettimeofday(struct timeval *tp, void *tzp);
DESCRIPTION [Toc] [Back]
The gettimeofday() function obtains the current time, expressed as
seconds and microseconds since Epoch, and stores it in the timeval
structure pointed to by tp.
The resolution of the system clock is one microsecond.
PARAMETERS [Toc] [Back]
Programs should use this time zone information only in the absence of
the TZ environment variable.
tp A pointer to a timeval structure in which the current time is
returned.
The timeval structure includes the following members:
time_t tv_sec /* Seconds. */
long tv_usec /* Microseconds. */
tzp If this parameter is not a null pointer, it is interpreted as a
pointer to a timezone structure under HP-UX. The timezone
structure has the following fields:
tz_minuteswest The number of minutes that the local time zone is
west of Coordinated Universal Time (UTC) or Epoch.
tz_dsttime A flag that, if nonzero, indicates that Daylight
Savings Time (DST) applies locally during the
appropriate part of the year.
RETURN VALUE [Toc] [Back]
gettimeofday() returns the following values under HP-UX:
0 Successful completion.
-1 Failure. errno is set to indicate the error.
ERRORS [Toc] [Back]
If gettimeofday() fails, errno is set to the following value under
HP-UX:
[EFAULT] An argument address referenced invalid memory.
Hewlett-Packard Company - 1 - HP-UX 11i Version 2: August 2003
gettimeofday(2) gettimeofday(2)
EXAMPLES [Toc] [Back]
The following HP-UX example calls gettimeofday() twice. It then
computes the lapsed time between the calls in seconds and microseconds
and stores the result in a timeval structure:
struct timeval first,
second,
lapsed;
struct timezone tzp;
gettimeofday (&first, &tzp);
/* lapsed time */
gettimeofday (&second, &tzp);
if (first.tv_usec > second.tv_usec) {
second.tv_usec += 1000000;
second.tv_sec--;
}
lapsed.tv_usec = second.tv_usec - first.tv_usec;
lapsed.tv_sec = second.tv_sec - first.tv_sec;
WARNINGS [Toc] [Back]
Relying on a granularity of one microsecond may result in code that is
not portable to other platforms.
AUTHOR [Toc] [Back]
gettimeofday() was developed by the University of California,
Berkeley, and HP.
SEE ALSO [Toc] [Back]
date(1), ftime(2), settimeofda(2), stime(2), time(2), ctime(3C).
Hewlett-Packard Company - 2 - HP-UX 11i Version 2: August 2003 [ Back ] |