CLOCKS_PER_SEC
From cppreference.com
                    
                                        
                    
                    
                                                            
                    | Defined in header  <ctime> | ||
| #define CLOCKS_PER_SEC /*implementation defined*/ | ||
Expands to an expression (not necessarily a compile-time constant) of type std::clock_t equal to the number of clock ticks per second, as returned by std::clock().
Notes
POSIX defines CLOCKS_PER_SEC as one million, regardless of the actual precision of std::clock().
See also
| returns raw processor clock time since the program is started (function) | |
| process running time (typedef) | |
| C documentation for CLOCKS_PER_SEC | |