clock_getres()

Get the resolution of the clock

Synopsis:

#include <time.h>

int clock_getres( clockid_t clock_id, 
                  struct timespec * res );

Library:

libc

Description:

The clock_getres() function gets the resolution of the clock specified by clock_id and puts it into the buffer pointed to by res.

The res parameter points to a structure containing at least the following members:

time_t tv_sec: This field is zero.
long tv_nsec: The resolution of the clock, in nanoseconds.

Returns:

0: Success
-1: An error occurred (errno is set).

Errors:

EFAULT: A fault occurred trying to access the buffers provided.
EINVAL: Invalid clock_id.

Examples:

/*
 * This program prints out the clock resolution.
 */
#include <stdio.h>
#include <stdlib.h>
#include <time.h>

int main( void )
  {
    struct timespec res;

    if ( clock_getres( CLOCK_REALTIME, &res) == -1 ) {
      perror( "clock get resolution" );
      return EXIT_FAILURE;
    }
    printf( "Resolution is %ld micro seconds.\n",
          res.tv_nsec / 1000 );
    return EXIT_SUCCESS;
  }

Classification:

POSIX 1003.1 (Realtime Extensions)

Safety:
Cancellation point	No
Interrupt handler	No
Signal handler	Yes
Thread	Yes