Question

I want to return an NSMutableString in my Foundation program. However, I get the following error:

warning: Semantic Issue: Incompatible pointer to integer conversion
returning ‘NSMutableString *’ from a function with result type ‘int’

for the following code:

int main (int argc, const char * argv[])
{
    NSMutableString* result = @"testing";

    [pool drain];
    return result;
}

Answer 1

That’s your main function. As you can see from the declaration int main(), it returns an int. In fact, main() is only allowed to return an int, which indicates failure or success (generally 0 means success and any other number is a program-specific error code). You can’t return anything else there — it’s just part of the language. If you’re trying to print the string, you can use NSLog(@"%@", result) or printf("%s", [result UTF8String]).