__PPS__ wrote:
Will Bryant wrote:
__PPS__ wrote:
any ideas what's wrong, why clock() doesn't work anymore?
I'd hazard a guess that that's because it's measuring process CPU time rather than wall clock time. If you replace the thing you're timing with some solid computation, does clock() suddenly start giving the results you expect?
If I understand right, what you say is that these delays are due to interaction with the os and they are not counted by clock (for this process)?
clock() is supposed to indicate how much time the processor has spent running the process. It should exclude the time the process spends waiting for input/output operations to complete, or waiting in the runnable queue while other processes run. (Unfortunately in the MS C library (and maybe other C libraries for Windows) clock() indicates elapsed time since the process started, perhaps for compatibility with its behaviour under DOS, where the active process is never descheduled.) Ben.