sleep.c

   1 /*
   2     Copyright © 2013 Alastair Stuart
   3
   4     This program is open source software: you can redistribute it and/or modify
   5     it under the terms of the GNU General Public License as published by
   6     the Free Software Foundation, either version 3 of the License, or
   7     (at your option) any later version.
   8
   9     This program is distributed in the hope that it will be useful,
  10     but WITHOUT ANY WARRANTY; without even the implied warranty of
  11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  12     GNU General Public License for more details.
  13 */
  14
  15 #include <ctype.h>
  16 #include <stdio.h>
  17 #include <stdlib.h>
  18 #include <string.h>
  19
  20 #include <getopt.h>
  21 #include <unistd.h>
  22
  23 #define VERSION "0.01"
  24
  25 void usage(char* program)
  26 {
  27     printf("Usage: %s [number]\n", program);
  28     printf("Pauses for [number] seconds.\n"
  29            "\n"
  30            "    --help     Print this message.\n"
  31            "    --version  Show version info.\n");
  32 }
  33
  34 int main(int argc, char* argv[])
  35 {
  36     static struct option long_options[] = {
  37         {"help",      no_argument, NULL,  1},
  38         {"version",   no_argument, NULL,  2},
  39         {NULL, 0, NULL, 0}
  40     };
  41
  42     int c = 0;
  43     while ((c = getopt_long(argc, argv, "R",
  44                             long_options, NULL)) != -1)
  45     {
  46         switch (c)
  47         {
  48             case 1:
  49                 usage(argv[0]);
  50                 return 0;
  51             case 2:
  52                 printf("sleep (mutos) v"VERSION"\n");
  53                 return 0;
  54             default:
  55                 fprintf(stderr,"Run '%s --help' for usage.\n",
  56                                      argv[0]);
  57                 return 1;
  58         }
  59     }
  60
  61     if ((argc - optind) == 0) {
  62         fprintf(stderr, "%s: missing operand\n"
  63                         "Run '%s --help' for usage.\n",
  64                         argv[0], argv[0]);
  65         return 1;
  66     }
  67
  68     if ((argc - optind) > 1) {
  69         fprintf(stderr, "%s: too many operands\n"
  70                         "Run '%s --help' for usage.\n",
  71                         argv[0], argv[0]);
  72         return 1;
  73     }
  74
  75     // validate number
  76     for (size_t i = 0; i < strlen(argv[optind]); i++)
  77     {
  78         if (!isdigit(argv[optind][i])) {
  79             fprintf(stderr, "%s: invalid number: %s\n",
  80                              argv[0],            argv[optind]);
  81             return 1;
  82         }
  83     }
  84
  85     sleep(atoi(argv[optind]));
  86 }