extern declaration and function definition both in the same file

Question

I was just browsing through gcc source files. In gcc.c, I found something like

extern int main (int, char **);

int
main (int argc, cha         


        

Answer 1

The definition of the main function:

int main(int argc, char **argv) { ... }

is already a declaration is the prototyped syntax of the function main with external linkage. This means a prototyped declaration with extern just before the main definition is redundant.