sleep.c

//  Copyright (C) 2021 Benjamin Stürz
//  
//  This program is free software: you can redistribute it and/or modify
//  it under the terms of the GNU General Public License as published by
//  the Free Software Foundation, either version 3 of the License, or
//  (at your option) any later version.
//  
//  This program is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//  GNU General Public License for more details.
//  
//  You should have received a copy of the GNU General Public License
//  along with this program.  If not, see <https://www.gnu.org/licenses/>.

#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>

int main(int argc, char* argv[]) {
   if (argc != 2) {
   print_usage:
      puts("Usage: sleep time");
      return 1;
   }
   char* endp;
   unsigned long n = strtoul(argv[1], &endp, 10);
   if (*endp) goto print_usage;
   sleep(n);
   return 0;
}