Best practice when referring to a program's name in C

Question

What is considered best practice when referring to a program's name? I've seen:

#define PROGRAM_NAME "myprog"
printf("this is %s\n", PROGRAM_NAME);

as well as:

printf("this is %s\n", argv[0]);

I know, that the second approach will give me ./myprog rather than myprog when the program is not called from $PATH and that the first approach will guarantee consistence regarding the program's name.

But is there anything else, that makes one approach superior to the other?

Answer 1

The second approach is superior when you have multiple links. In *nix systems, sometimes behavior depends on how you call a program. So hard coding the program name would clearly be a problem -- it could never check that.

Answer 2

I tried to take the best of both worlds:

char const * program_name;

int main(int argc, char **argv) {
   program_name = argv[0];
   //...
}

If you need program_name to be available in some other file you can declare it like this:

extern char const * program_name;

I declare "char const *" because I want it to be a pointer which points to const data. I'm not sure if I did right this part.