settimeofday()--Set System Clock


  Syntax
 #include <sys/time.h>

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

  Service Program Name: QWCTZUTC

  Default Public Authority: *USE

  Threadsafe: Yes

The settimeofday() function sets the system clock to the Coordinated Universal Time (UTC) contained in the timeval structure pointed to by tp. The tzp parameter is not used.


Parameters

tp
(Input) 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
This parameter is not used.

Authorities and Locks

Special Authority
*ALLOBJ

Return Value

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

Error Conditions

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

[EACCES] Permission denied.

An attempt was made to access an object in a way forbidden by its object access permissions.
[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.
[EPERM] Operation not permitted.

You must have appropriate privileges or be the owner of the object or other resource to do the requested operation.
[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.


Related Information


Example

See Code disclaimer information for information pertaining to code examples.

The following example sets the system clock:

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

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

    now.tv_sec=866208142;
    now.tv_usec=290944;

    rc=settimeofday(&now, NULL);
    if(rc==0) {
        printf("settimeofday() successful.\n");
    }
    else {
        printf("settimeofday() failed, "
        "errno = %d\n",errno);
        return -1;
    }

    return 0;
}
Example Output: 
settimeofday() successful.

API introduced: V4R2
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