Timing code execution

[kencat742]

I am writing a program which needs to send commands to the RS-232 port to turn valves on and off. I have that part done, but now i need to be able to time it so that it will go automatically. This has to be exact to the millisecond. From what i've read I'm assuming that I need to use QueryPerformanceCounter/QueryPerformanceFrequency but I am having difficulties finding the syntax for these commands. Any help would be much appreciated. Thanks

 

[vladk]

kencat742,

For milliseconds Timer control is sufficient in most cases.

Timer1.Interval = 1 means one millisecond

vladk

 

[kencat742]

I thought that timer was only as accurate as the system clock which is 10ms in XP

 

[strongm]

Correct, kencat742 (well, depends on the version of XP, but correct enough).

Thread222-508991 has a succint example of the high performance counters (although it is worth pointing out that the multimedia timers - timeGetTime etc. - are accurate to 1ms, as per the requirements of the MIDI standard).

For those that want to know a little bit more about (current*) timing capabilities in Windows, try thread222-495997



* Microsoft and Intel have agreed a much higher precision timing standard for future Windows versions - but I can't find the relevant URL references at the moment.

 

[BobRodes]

http://www.microsoft.com/whdc/system/CEC/mm-timer.mspx#EEAA

This looks like it.

 

[strongm]

That's the one!