Odd Sleep() Within Thread Behavior

[novacain]

A better technique might be to use a timer with a callback to your code. These are not pinpoint accurate either (+ - about 2ms) but they're going to be more accurate than Sleep()ing.

WM_TIMER msgs are THE lowest priority in the OS msg queue, after WM_PAINT.

Getting a consistent resolution of +/- 2 msec is impossible, getting +/- 50 msec is hard in any system under load.

There are also techniques using GetTickCount() --a 1 millisecond heartbeat-- that should get you within a millisecond. Something like if(! GetTickCount() % 20) might be just what you need...

GetTickCount is a low performance timer using the system timer, which has a minimum resolution of ~10 msec (closer to 15 msec on the sytems I use).

I found it very difficult to get sub to one millisec timers on MS OS's (except CE) without using a filter driver.

QueryPerformanceCounter() is much better resolution, but may have issues on threads running on differing cores of a multi core CPU (and if not implemented on the system hardware will default to call GetTickCount()).