clock_t

Defined in header `<time.h>`
typedef /* unspecified */ clock_t;

Arithmetic(until C11)Real(since C11) type capable of representing the processor time used by a process. It has implementation-defined range and precision.

Example

#include <stdio.h>
#include <time.h>
#include <math.h>
 
volatile double sink;
int main (void)
{
  clock_t start = clock();
 
  for(size_t i=0; i<3141592; ++i)
      sink+=sin(i);
 
  clock_t end = clock();
  double cpu_time_used = ((double) (end - start)) / CLOCKS_PER_SEC;
 
  printf("for loop took %f seconds to execute \n", cpu_time_used);
}

Possible output:

for loop took 0.271828 seconds to execute

References

C17 standard (ISO/IEC 9899:2018):

7.27.1/3 Components of time (p: 284)

C11 standard (ISO/IEC 9899:2011):

7.27.1/3 Components of time (p: 388)

C99 standard (ISO/IEC 9899:1999):

7.23.1/3 Components of time (p: 338)

C89/C90 standard (ISO/IEC 9899:1990):

4.12.1 Components of time

clock	returns raw processor clock time since the program is started (function)
CLOCKS_PER_SEC	number of processor clock ticks per second (macro constant)
C++ documentation for `clock_t`

clock_t

Example

References

See also