glibc/manual/examples/argp-ex4.c

/* Argp example #4 -- a program with somewhat more complicated options */

#include <stdlib.h>
#include <error.h>
#include <argp.h>

const char *argp_program_version =
  "argp-ex4 1.0";
const char *argp_program_bug_address =
  "<bug-gnu-utils@@prep.ai.mit.edu>";

/* Program documentation.  */
static char doc[] =
  "Argp example #4 -- a program with somewhat more complicated\
options\
\vThis part of the documentation comes *after* the options;\
 note that the text is automatically filled, but it's possible\
 to force a line-break, e.g.\n<-- here.";

/* A description of the arguments we accept.  */
static char args_doc[] = "ARG1 [STRING...]";

/* Keys for options without short-options.  */
#define OPT_ABORT  1		/* --abort */

/* The options we understand.  */
static struct argp_option options[] = {
  {"verbose",  'v', 0,       0, "Produce verbose output" },
  {"quiet",    'q', 0,       0, "Don't produce any output" },
  {"silent",   's', 0,       OPTION_ALIAS },
  {"output",   'o', "FILE",  0,
   "Output to FILE instead of standard output" },

  {0,0,0,0, "The following options should be grouped together:" },
  {"repeat",   'r', "COUNT", OPTION_ARG_OPTIONAL,
   "Repeat the output COUNT (default 10) times"},
  {"abort",    OPT_ABORT, 0, 0, "Abort before showing any output"},

  { 0 }
};

/* Used by @code{main} to communicate with @code{parse_opt}.  */
struct arguments
{
  char *arg1;			/* @var{arg1} */
  char **strings;		/* [@var{string}@dots{}] */
  int silent, verbose, abort;	/* @samp{-s}, @samp{-v}, @samp{--abort} */
  char *output_file;		/* @var{file} arg to @samp{--output} */
  int repeat_count;		/* @var{count} arg to @samp{--repeat} */
};

/* Parse a single option.  */
static error_t
parse_opt (int key, char *arg, struct argp_state *state)
{
  /* Get the @code{input} argument from @code{argp_parse}, which we
     know is a pointer to our arguments structure.  */
  struct arguments *arguments = state->input;

  switch (key)
    {
    case 'q': case 's':
      arguments->silent = 1;
      break;
    case 'v':
      arguments->verbose = 1;
      break;
    case 'o':
      arguments->output_file = arg;
      break;
    case 'r':
      arguments->repeat_count = arg ? atoi (arg) : 10;
      break;
    case OPT_ABORT:
      arguments->abort = 1;
      break;

    case ARGP_KEY_NO_ARGS:
      argp_usage (state);

    case ARGP_KEY_ARG:
      /* Here we know that @code{state->arg_num == 0}, since we
	 force argument parsing to end before any more arguments can
	 get here.  */
      arguments->arg1 = arg;

      /* Now we consume all the rest of the arguments.
	 @code{state->next} is the index in @code{state->argv} of the
	 next argument to be parsed, which is the first @var{string}
	 we're interested in, so we can just use
	 @code{&state->argv[state->next]} as the value for
	 arguments->strings.

	 @emph{In addition}, by setting @code{state->next} to the end
	 of the arguments, we can force argp to stop parsing here and
	 return.  */
      arguments->strings = &state->argv[state->next];
      state->next = state->argc;

      break;

    default:
      return ARGP_ERR_UNKNOWN;
    }
  return 0;
}

/* Our argp parser.  */
static struct argp argp = { options, parse_opt, args_doc, doc };

int main (int argc, char **argv)
{
  int i, j;
  struct arguments arguments;

  /* Default values.  */
  arguments.silent = 0;
  arguments.verbose = 0;
  arguments.output_file = "-";
  arguments.repeat_count = 1;
  arguments.abort = 0;

  /* Parse our arguments; every option seen by @code{parse_opt} will be
     reflected in @code{arguments}.  */
  argp_parse (&argp, argc, argv, 0, 0, &arguments);

  if (arguments.abort)
    error (10, 0, "ABORTED");

  for (i = 0; i < arguments.repeat_count; i++)
    {
      printf ("ARG1 = %s\n", arguments.arg1);
      printf ("STRINGS = ");
      for (j = 0; arguments.strings[j]; j++)
	printf (j == 0 ? "%s" : ", %s", arguments.strings[j]);
      printf ("\n");
      printf ("OUTPUT_FILE = %s\nVERBOSE = %s\nSILENT = %s\n",
	      arguments.output_file,
	      arguments.verbose ? "yes" : "no",
	      arguments.silent ? "yes" : "no");
    }

  exit (0);
}