get number of CPUs in C++ MFC application

Question

I write a little raytracer and i'd like to query how many cpu cores (or virtual cpu cores if the cpu uses hyperthreading) the current computer offers, such that i can instanciate as many threads to get better parallel rendering.

How can I do that using C++?

thanks!

I am not sure, but looks like a duplicate of http://stackoverflow.com/questions/150355/programmatically-find-the-number-of-cores-on-a-machine — Naveen, Nov 11 '09 at 17:48

score 8 · Accepted Answer · answered Nov 11 '09 at 17:51

8

You can get the number of physical processors by calling GetSystemInfo and checking the dwNumberOfProcessors field of the SYSTEM_INFO structure. You can get the number of logical processors by calling GetLogicalProcessorInformation.

answered Nov 11 '09 at 17:51

Nick Meyer

39,212
14
67
75

BTW: GetLogicalProcessorInformation doesn't work on XP before SP3 – naugtur May 06 '10 at 11:01

score 2 · Answer 2 · answered Nov 11 '09 at 17:51

2

Try the GetSystemInfo function. It returns a SYSTEM_INFO struct which has a dwNumberOfProcessors member.

answered Nov 11 '09 at 17:51

luke

36,103
8
58
81

score 2 · Answer 3 · answered Nov 11 '09 at 17:53

2

The Win32 API function GetSystemInfo will return a SYSTEM_INFO structure with the information you need. Specifically, check the dwNumberOfProcessors member variable.

answered Nov 11 '09 at 17:53

Russell Newquist

2,656
2
16
18

get number of CPUs in C++ MFC application

3 Answers3