manual/examples/argp-ex3.c

   1 /* Argp example #3 -- a program with options and arguments using argp */
   2
   3 #include <argp.h>
   4
   5 const char *argp_program_version =
   6   "argp-ex3 1.0";
   7 const char *argp_program_bug_address =
   8   "<bug-gnu-utils@@prep.ai.mit.edu>";
   9
  10 /* Program documentation.  */
  11 static char doc[] =
  12   "Argp example #3 -- a program with options and arguments using argp";
  13
  14 /* A description of the arguments we accept.  */
  15 static char args_doc[] = "ARG1 ARG2";
  16
  17 /* The options we understand.  */
  18 static struct argp_option options[] = {
  19   {"verbose",  'v', 0,      0,  "Produce verbose output" },
  20   {"quiet",    'q', 0,      0,  "Don't produce any output" },
  21   {"silent",   's', 0,      OPTION_ALIAS },
  22   {"output",   'o', "FILE", 0,
  23    "Output to FILE instead of standard output" },
  24   { 0 }
  25 };
  26
  27 /* Used by @code{main} to communicate with @code{parse_opt}.  */
  28 struct arguments
  29 {
  30   char *args[2];                /* @var{arg1} & @var{arg2} */
  31   int silent, verbose;
  32   char *output_file;
  33 };
  34
  35 /* Parse a single option.  */
  36 static error_t
  37 parse_opt (int key, char *arg, struct argp_state *state)
  38 {
  39   /* Get the @var{input} argument from @code{argp_parse}, which we
  40      know is a pointer to our arguments structure.  */
  41   struct arguments *arguments = state->input;
  42
  43   switch (key)
  44     {
  45     case 'q': case 's':
  46       arguments->silent = 1;
  47       break;
  48     case 'v':
  49       arguments->verbose = 1;
  50       break;
  51     case 'o':
  52       arguments->output_file = arg;
  53       break;
  54
  55     case ARGP_KEY_ARG:
  56       if (state->arg_num >= 2)
  57         /* Too many arguments.  */
  58         argp_usage (state);
  59
  60       arguments->args[state->arg_num] = arg;
  61
  62       break;
  63
  64     case ARGP_KEY_END:
  65       if (state->arg_num < 2)
  66         /* Not enough arguments.  */
  67         argp_usage (state);
  68       break;
  69
  70     default:
  71       return ARGP_ERR_UNKNOWN;
  72     }
  73   return 0;
  74 }
  75
  76 /* Our argp parser.  */
  77 static struct argp argp = { options, parse_opt, args_doc, doc };
  78
  79 int main (int argc, char **argv)
  80 {
  81   struct arguments arguments;
  82
  83   /* Default values.  */
  84   arguments.silent = 0;
  85   arguments.verbose = 0;
  86   arguments.output_file = "-";
  87
  88   /* Parse our arguments; every option seen by @code{parse_opt} will
  89      be reflected in @code{arguments}.  */
  90   argp_parse (&argp, argc, argv, 0, 0, &arguments);
  91
  92   printf ("ARG1 = %s\nARG2 = %s\nOUTPUT_FILE = %s\n"
  93           "VERBOSE = %s\nSILENT = %s\n",
  94           arguments.args[0], arguments.args[1],
  95           arguments.output_file,
  96           arguments.verbose ? "yes" : "no",
  97           arguments.silent ? "yes" : "no");
  98
  99   exit (0);
 100 }