   Get CPU temperature
  What's the easiest way to read the CPU temperature from C++ in 1) Windows and 2) Linux?  I need to control some hardware external to the computer based on the CPU temperature.   
  It depends on the chipset and drivers. They may expose some interface for you to retrieve this information. Check with the mobo manufacturer to see if they have an SDK.Otherwise there may be generic temp getter SDK's available. Or worse case you'll need to add the temperature sensor and some kind of board from which you can read it.http://www.google.com/search?q=get+cpu+temperature;  The guys behind SpeedFan could probably give you lots of details.  (Of course, you may want/need to offer them something in return.)   