Return number of clock ticks since process start.
  Returns the number of clock ticks elapsed.
  A macro constant called CLK_TCK defines the relation betwen clock tick and second (clock ticks per second).

Parameters.

(none)

Return Value.
  The number of clock ticks elapsed since start.
  clock_t type is defined by default as long int by most compilers.

Portability.
  Defined in ANSI-C.

Example.

/* clock example: countdown */
#include <stdio.h>
#include <time.h>

void wait ( int seconds )
{
  clock_t endwait;
  endwait = clock () + seconds * CLK_TCK ;
  while (clock() < endwait) {}
}

main ()
{
  int n;
  printf ("Starting countdown...\n");
  for (n=10; n>0; n--)
  {
    printf ("%d\n",n);
    wait (1);
  }
  printf ("FIRE!!!\n");
  return 0;
}

See also.
  time, difftime