测试CPU核心个数

//测试CPU核心个数
#if !defined (_WIN32) && !defined (_WIN64)
#define LINUX
#include <unistd.h>
#else
#define WINDOWS
#include <windows.h>
#endif
unsigned core_count()
{
  unsigned count = ; // 至少一个
  #if defined (LINUX)
  count = sysconf(_SC_NPROCESSORS_CONF);
  #elif defined (WINDOWS)
  SYSTEM_INFO si;
  GetSystemInfo(&si);
  count = si.dwNumberOfProcessors;
  #endif
  return count;
}
#include <iostream>
int main()
{
  unsigned sz = core_count();
  std::cout << sz << ( == sz ? "core" : "cores") << std::endl;
}

http://www.cppblog.com/Chipset/archive/2009/02/20/74403.html