# clock_t

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< c‎ | chrono

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

Run this code

    #include <stdio.h>
    #include <time.h>

    volatile unsigned sink;
    int main (void)
    {
      clock_t start = clock();

      for(size_t i=0; i<10000000; ++i)
          sink++;

      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 0.033492 seconds to execute

### References

- 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

### See also

clock | returns raw processor clock time since the program is started (function)
CLOCKS_PER_SEC | number of processor clock ticks per second (macro constant)

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