After testing on msvc8, I found: Parse GetCommandLine() to argc and argv Standard C Library initialization C++ Constructor of global variables These three things are called before entering main(). My questions are: Will this execution order be different when I porting my program to different compiler (gcc or armcc), or different platform? What stuff does Standard C Library initialization do? So far I know setlocale() is a must. Is it safe to call standard C functions inside C++ constructor of global variables?