The header file should be put:
# 1 function prototype declaration
# 2 The global variable declares that this is nothing to define. That is: Extern Int Global;
# 3 ourselves defined macros and types
The following is not to put it:
# 1 Definition of global variables and functions The global variable can only be defined once, if INT GLOBAL; in the header file, then all places containing this header file define a global variable global, when the link is connected I will report to find multiple Global. The situation of the function is also the truth, because the name of the function should be unique in the global space.
# 2 static variables and static functions This is also obvious, Static is originally to prevent global visible.
