coreutils

// logname.c, version 1.0.1
// OMKOV coreutils implementation of POSIX logname
// Copyright (C) 2020, Jakob Wakeling
// MIT Licence

#include "util/error.h"

#include <unistd.h>

#include <stdio.h>

int main(void) {
	register char *login = getlogin();
	if (!login) { error(1, "%s", serr()); }
	else { puts(login); } return 0;
}