manual/examples/argp-ex4.c

   1 /* Argp example #4 -- a program with somewhat more complicated options */
   2
   3 /* This program uses the same features as example 3, but has more
   4    options, and somewhat more structure in the -help output.  It
   5    also shows how you can `steal' the remainder of the input
   6    arguments past a certain point, for programs that accept a
   7    list of items.  It also shows the special argp KEY value
   8    ARGP_KEY_NO_ARGS, which is only given if no non-option
   9    arguments were supplied to the program.
  10
  11    For structuring the help output, two features are used,
  12    *headers* which are entries in the options vector with the
  13    first four fields being zero, and a two part documentation
  14    string (in the variable DOC), which allows documentation both
  15    before and after the options; the two parts of DOC are
  16    separated by a vertical-tab character ('\v', or '\013').  By
  17    convention, the documentation before the options is just a
  18    short string saying what the program does, and that afterwards
  19    is longer, describing the behavior in more detail.  All
  20    documentation strings are automatically filled for output,
  21    although newlines may be included to force a line break at a
  22    particular point.  All documentation strings are also passed to
  23    the `gettext' function, for possible translation into the
  24    current locale.  */
  25
  26 #include <stdlib.h>
  27 #include <error.h>
  28 #include <argp.h>
  29
  30 const char *argp_program_version =
  31   "argp-ex4 1.0";
  32 const char *argp_program_bug_address =
  33   "<bug-gnu-utils@@prep.ai.mit.edu>";
  34
  35 /* Program documentation.  */
  36 static char doc[] =
  37   "Argp example #4 -- a program with somewhat more complicated\
  38 options\
  39 \vThis part of the documentation comes *after* the options;\
  40  note that the text is automatically filled, but it's possible\
  41  to force a line-break, e.g.\n<-- here.";
  42
  43 /* A description of the arguments we accept.  */
  44 static char args_doc[] = "ARG1 [STRING...]";
  45
  46 /* Keys for options without short-options.  */
  47 #define OPT_ABORT  1            /* --abort */
  48
  49 /* The options we understand.  */
  50 static struct argp_option options[] = {
  51   {"verbose",  'v', 0,       0, "Produce verbose output" },
  52   {"quiet",    'q', 0,       0, "Don't produce any output" },
  53   {"silent",   's', 0,       OPTION_ALIAS },
  54   {"output",   'o', "FILE",  0,
  55    "Output to FILE instead of standard output" },
  56
  57   {0,0,0,0, "The following options should be grouped together:" },
  58   {"repeat",   'r', "COUNT", OPTION_ARG_OPTIONAL,
  59    "Repeat the output COUNT (default 10) times"},
  60   {"abort",    OPT_ABORT, 0, 0, "Abort before showing any output"},
  61
  62   { 0 }
  63 };
  64
  65 /* Used by @code{main} to communicate with @code{parse_opt}.  */
  66 struct arguments
  67 {
  68   char *arg1;                   /* @var{arg1} */
  69   char **strings;               /* [@var{string}@dots{}] */
  70   int silent, verbose, abort;   /* @samp{-s}, @samp{-v}, @samp{--abort} */
  71   char *output_file;            /* @var{file} arg to @samp{--output} */
  72   int repeat_count;             /* @var{count} arg to @samp{--repeat} */
  73 };
  74
  75 /* Parse a single option.  */
  76 static error_t
  77 parse_opt (int key, char *arg, struct argp_state *state)
  78 {
  79   /* Get the @code{input} argument from @code{argp_parse}, which we
  80      know is a pointer to our arguments structure.  */
  81   struct arguments *arguments = state->input;
  82
  83   switch (key)
  84     {
  85     case 'q': case 's':
  86       arguments->silent = 1;
  87       break;
  88     case 'v':
  89       arguments->verbose = 1;
  90       break;
  91     case 'o':
  92       arguments->output_file = arg;
  93       break;
  94     case 'r':
  95       arguments->repeat_count = arg ? atoi (arg) : 10;
  96       break;
  97     case OPT_ABORT:
  98       arguments->abort = 1;
  99       break;
 100
 101     case ARGP_KEY_NO_ARGS:
 102       argp_usage (state);
 103
 104     case ARGP_KEY_ARG:
 105       /* Here we know that @code{state->arg_num == 0}, since we
 106          force argument parsing to end before any more arguments can
 107          get here.  */
 108       arguments->arg1 = arg;
 109
 110       /* Now we consume all the rest of the arguments.
 111          @code{state->next} is the index in @code{state->argv} of the
 112          next argument to be parsed, which is the first @var{string}
 113          we're interested in, so we can just use
 114          @code{&state->argv[state->next]} as the value for
 115          arguments->strings.
 116
 117          @emph{In addition}, by setting @code{state->next} to the end
 118          of the arguments, we can force argp to stop parsing here and
 119          return.  */
 120       arguments->strings = &state->argv[state->next];
 121       state->next = state->argc;
 122
 123       break;
 124
 125     default:
 126       return ARGP_ERR_UNKNOWN;
 127     }
 128   return 0;
 129 }
 130
 131 /* Our argp parser.  */
 132 static struct argp argp = { options, parse_opt, args_doc, doc };
 133
 134 int main (int argc, char **argv)
 135 {
 136   int i, j;
 137   struct arguments arguments;
 138
 139   /* Default values.  */
 140   arguments.silent = 0;
 141   arguments.verbose = 0;
 142   arguments.output_file = "-";
 143   arguments.repeat_count = 1;
 144   arguments.abort = 0;
 145
 146   /* Parse our arguments; every option seen by @code{parse_opt} will be
 147      reflected in @code{arguments}.  */
 148   argp_parse (&argp, argc, argv, 0, 0, &arguments);
 149
 150   if (arguments.abort)
 151     error (10, 0, "ABORTED");
 152
 153   for (i = 0; i < arguments.repeat_count; i++)
 154     {
 155       printf ("ARG1 = %s\n", arguments.arg1);
 156       printf ("STRINGS = ");
 157       for (j = 0; arguments.strings[j]; j++)
 158         printf (j == 0 ? "%s" : ", %s", arguments.strings[j]);
 159       printf ("\n");
 160       printf ("OUTPUT_FILE = %s\nVERBOSE = %s\nSILENT = %s\n",
 161               arguments.output_file,
 162               arguments.verbose ? "yes" : "no",
 163               arguments.silent ? "yes" : "no");
 164     }
 165
 166   exit (0);
 167 }