sleep.c

   1 /* `sleep.c` - suspend execution for an interval
   2    Copyright (c) 2022, Alan Potteiger
   3    See `LICENSE` for copyright and license details */
   4
   5 #define _POSIX_C_SOURCE 200809L
   6
   7 #include <stdio.h>
   8 #include <stdlib.h>
   9 #include <errno.h>
  10 #include <unistd.h>
  11
  12 static const char *usage = {
  13         "usage: sleep time\n"
  14 };
  15
  16 /* this is the first utility cause I'm tired as hell */
  17
  18 int
  19 main(int argc, char *argv[])
  20 {
  21         long sec;
  22
  23         if (argc < 2) {
  24                 fputs(usage, stderr);
  25                 return 1;
  26         }
  27
  28         sec = strtol(argv[1], NULL, 10);
  29         if (sec == 0 && errno == EINVAL) {
  30                 perror("sleep");
  31                 fputs(usage, stderr);
  32                 return 1;
  33         }
  34
  35         sleep((unsigned int) sec);
  36
  37         return 0;
  38 }
  39