CLI Arguments ignore

You'll always get at least 1 argument when main is called by the environment, the program name, in all environments I know of (but it's not mandated to be called with at least 1 argument and some embedded environments may call it with 0). To force it being called with 0 arguments, you could call main yourself:

int main(int argc, char* argv[])
{
    if (argc != 0) {
        return main(0, argv + argc); // main called with argc == 0
    }
    // the rest of the function left unchanged

Proof of "zero arguments possible" by counter-example

#include 
#include 
#include 
#include 
int main(int argc, char argv)
{
    char prog = "argc37";
    if (argc > 2)
        fprintf(stderr, "Usage: %s [program]\n", argv[0]);
    else
    {
        if (argc == 2)
            prog = argv[1];
        char args[] = { NULL };
        execv(prog, args);
        fprintf(stderr, "%s: failed to execute '%s' with zero arguments (%d: %s)\n",
                argv[0], prog, errno, strerror(errno));
    }
    return 1;
}

#include 
// When calling just, pass a different amount of arguments: just run 6 arg1 arg2 ...;
int main(int argc, char* argv[])
{
    // This is impossible because there is always a command name
    if (argc