Clock

from cplusplus reference

clock_t clock (void)

Returns the processor time consumed by the program.

The value returned is expressed in clock ticks, which are units of time of a constant but system-specific length (with a relation of CLOCKS_PER_SEC clock ticks per second).

The epoch used as reference by clock varies between systems, but it is related to the program execution (generally its launch). To calculate the actual processing time of a program, the value returned by clock shall be compared to a value returned by a previous call to the same function.

Return Value:

The number of clock ticks elapsed since an epoch related to the particular program execution.

On failure, the function returns a value of -1.

clock_t is a type defined in as an alias of a fundamental arithmetic type.