cgccc99

GCC C99 Disable compilation of main() without return

How to force gcc compilator throw error when int main() have no return statement. This code compiles without any errors

#include<stdio.h>

int main(){
   printf("Hi");
}

I am using

gcc  -Wall -Wextra -std=c99 -Wreturn-type -Werror -pedantic-errors a.c

command for compilation

Solution

  • You can avoid the special treatment that main receives by renaming it. Compiling with -Dmain=AlternateName -Werror=return-type yields “error: control reaches end of non-void function”.

    Naturally, you would do this as a special compilation to test for the issue and not use the object module resulting from this compilation. A second normal compilation without -Dmain=AlternateName would be used to generate the object module.