### __rdtsc -- Read Time Stamp Counter

Format

>     #include <builtin.h>

>     unsigned long long __rdtsc(void)

Language Level: None
__rdtsc returns the current value of the processor's time-stamp counter. The processor increments the time-stamp counter every clock cycle and resets it to 0 whenever the processor is reset. This builtin function will not work on a 386 or 486 processor.

Return Value
Returns the current value of the processor's time-stamp counter.

Example
This example prints out the current value of the processor's time-stamp counter.

    #include <stdio.h>
    #include <builtin.h>

    int main(void)
    {
       printf("The time stamp counter value is %.8llx\n", __rdtsc());

       /*************************************************************
          The output should be (the actual counter value will vary):

          The time stamp counter value is 53af6dd46631
       *************************************************************/

       return 0;
    }