GetProcessAffinity on Quad core CPU

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Ed - 27 Jan 2007 13:42 GMT

Just wondering if anyone knows what the return values are for
GetProcessAffinity using a quad core CPU, using code below works fine
for dual core.

'/// Get CPU affinty for Process ID on dual core CPU ///

RetVal = GetProcessAffinity(PID)

Select Case RetVal
Case 3
Affinty = "0+1" 'CPU 0 and CPU 1
Case 2
Affinty = "1" 'CPU 1
Case 1
Affinty = "0" 'CPU 0
End Select

I don't have a quad yet but would like to get a head start on updating
one of my programs.

Thanks,
Ed

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Mike D Sutton - 27 Jan 2007 21:41 GMT

> Just wondering if anyone knows what the return values are for
> GetProcessAffinity using a quad core CPU, using code below works fine
[quoted text clipped - 15 lines]
> I don't have a quad yet but would like to get a head start on updating
> one of my programs.

It simply returns a bit-mask of the processors:

Processor 1 = 0x1 = 0001b
Processor 2 = 0x2 = 0010b
Processor 3 = 0x4 = 0100b
Processor 4 = 0x8 = 1000b
Processor n = (2 ^ n)

So for four processors 1 through 4 you would use an affinity mask of 0x1 + 0x2 + 0x4 + 0x8 = 0xF.
Here's an old thread with some more information and examples on the call:
http://groups.google.co.uk/group/microsoft.public.vb.winapi/msg/83e88190612c4212
Hope this helps,

Mike

- Microsoft Visual Basic MVP -
E-Mail: EDais@mvps.org
WWW: Http://EDais.mvps.org/

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Ed - 28 Jan 2007 00:47 GMT

>Processor 1 = 0x1 = 0001b
>Processor 2 = 0x2 = 0010b
>Processor 3 = 0x4 = 0100b
>Processor 4 = 0x8 = 1000b

OK, I think it sunk in now! ;)

Cheers, (holding up coffee cup)
Thanks again,
Ed

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VB Forum / Win API / January 2007

GetProcessAffinity on Quad core CPU