Question

I was reading some samples of code, and they returned a const int. When I tried to compile the examples code I got errors concerning conflicting return types. So I started searching, thinking that the const was the problem (when I removed it, the code worked fine, not only did it compile, but worked as expected). But I never was able to find information specifically pertaining to a const return type (I did for structures/parameters/etc. etc., but not return types). So I tried writing a piece of code to simply show what const may do. I came up with this:

#include <stdio.h>

int main() {
    printf("%i", method());
}

const int method() {
    return 5;
}

And when I compile this, I get:

$ gcc first.c 
first.c:7: error: conflicting types for ‘method’
first.c:4: note: previous implicit declaration of ‘method’ was here

However, whenever I remove the const, it, as expected, simply prints out a 5, a continues on with life. So, can anyone tell me what const is supposed to mean when used as a return type. Thank you.

Answer 1

Adding the prototype of method() before you call it will fix the error.

const int method();
int main() {
    printf("%i", method());
}

---

Line 7: error: conflicting types for 'method'

This error tells us that method() was created by the compiler (because it didn’t find it) with a different return type than const int (probably int).

Line 4: error: previous implicit declaration of 'method' was here

This other error tells us that in fact the compiler created its own version of method.