clock
| Defined in header <time.h>
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| clock_t clock(); |
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Returns the approximate processor time used by the process since the beginning of an implementation-defined era related to the program's execution. To convert result value to seconds divide it by CLOCKS_PER_SEC. Because the beginning of the clock era does not have to coincide with the start of the program, only the difference between two values returned by different calls to clock is meaningful. If the CPU is shared by other processes, clock time may advance slower than wall clock. If the current process is multithreaded and more than one execution core is available, clock time may advance faster than wall clock.
Contents |
[edit] Parameters
(none)
[edit] Return value
Processor time used by the program so far or (clock_t)(-1) if that information is unavailable.
[edit] Notes
On POSIX-compatible systems, clock_gettime with clock id CLOCK_PROCESS_CPUTIME_ID offers better resolution.
The value returned by clock() may wrap around on some implementations. For example, on a machine with 32-bit clock_t, it wraps after 2147 seconds or 36 minutes.
clock() is not required to be thread-safe.
[edit] Example
| This section is incomplete Reason: no example |
[edit] See also
| converts a tm object to a textual representation (function) | |
| returns the current time of the system as time since epoch (function) | |
| C++ documentation for clock
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