Question

When externing a function in the cpp file does the compiler treat these differently?

extern void foo(char * dataPtr);  
void foo(char *);
extern void foo(char * );  

I am wondering because I have see all these in code and not sure what the difference is.

Answer 1

Case by case:

 extern void foo(char * dataPtr);  

functions have external linkage by default, so the extern is not necessary – this is equivalent to:

 void foo(char * dataPtr);

Parameter names are not significant in function declarations, so the above is equivalent to:

 void foo(char * );  

Use whichever you feel happiest with.