C++ performance of global variables

Question

For clarification: I know how evil globals are and when not to use them :)

• Is there any performance penalty when accessing/setting a global variable vs. a loca

Answer 1

That would depend entirely on your machine architecture. Global variables are accessed via a single known address, whereas local variables are typically accessed by indexing off an address register. The chances of the difference between the two being significant is extremely remote, but if you think it will be important, you should write a test for your target architecture and measure the difference.