Programmatically find the number of cores on a machine

Question

Is there a way to determine how many cores a machine has from C/C++ in a platform-independent way? If no such thing exists, what about determining it per-platform (Windows/*

Answer 1

If you have assembly-language access, you can use the CPUID instruction to get all sorts of information about the CPU. It's portable between operating systems, though you'll need to use manufacturer-specific information to determine how to find the number of cores. Here's a document that describes how to do it on Intel chips, and page 11 of this one describes the AMD specification.