gettimeofday()--Get Current UTC Time

Syntax

 #include <sys/time.h>

 int gettimeofday (struct timeval *tp,
                   struct timezone *tzp);

  Service Program Name:QWCTZUTC

  Default Public Authority: *USE

  Threadsafe: Yes

The gettimeofday() function retrieves the current Coordinated Universal Time (UTC) and places it in the timeval structure pointed to by tp. If tzp is not NULL, the time zone information is returned in the time zone structure pointed to by tzp.

Parameters

tp: (Output) A pointer to a timeval structure that contains the time in seconds and microseconds since 1 January 1970, 00:00:00 UTC (epoch-1970).
tzp: (Output) A pointer to a time zone structure that contains the local time zone (measured in minutes west of Greenwich) and a flag that, if nonzero, indicates Daylight Saving Time applies locally during the appropriate part of the year.

Authorities and Locks

None

Return Value

0	gettimeofday() was successful.
-1	gettimeofday() was not successful. The `errno` variable is set to indicate the error.

Error Conditions

If gettimeofday() is not successful, errno usually indicates one of the following errors. Under some conditions, errno could indicate an error other than those listed here.

[EINVAL]

An invalid parameter was found.

A parameter passed to this function is not valid.

[EFAULT]

The address used for an argument is not correct.

In attempting to use an argument in a call, the system detected an address that is not valid.

While attempting to access a parameter passed to this function, the system detected an address that is not valid.

[EUNKNOWN]

Unknown system state.

The operation failed because of an unknown system state. See any messages in the job log and correct any errors that are indicated, then retry the operation.

Error Messages

None.

Usage Notes

For the best performance, specify NULL for the tzp parameter.

Related Information

The <sys/time.h> file (see Header Files for UNIX-Type Functions)
adjtime()--Adjust System Clock
ftime()--Get Date and Time
Qp0zCvtToMITime()--Convert Timeval Structure to _MI_ Time
settimeofday()--Set System Clock

Example

See Code disclaimer information for information pertaining to code examples.

The following example gets the current UTC time:

#include <sys/time.h>
#include <stdio.h>
#include <errno.h>

int main(int argc, char *argv[])
{
    struct timeval now;
    int rc;

    rc=gettimeofday(&now, NULL);
    if(rc==0) {
        printf("gettimeofday() successful.\n");
        printf("time = %u.%06u\n",
                now.tv_sec, now.tv_usec);
    }
    else {
        printf("gettimeofday() failed, errno = %d\n",
                errno);
        return -1;
    }

    return 0;
}

Example Output:

gettimeofday() successful.
time = 866208142.290944

API introduced: V4R2

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