170 lines
6.0 KiB
C
170 lines
6.0 KiB
C
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/* Argp example #3 -- a program with options and arguments using argp
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Copyright (C) 1991-2022 Free Software Foundation, Inc.
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; either version 2
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of the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, see <https://www.gnu.org/licenses/>.
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*/
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/* This program uses the same features as example 2, and uses options and
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arguments.
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We now use the first four fields in ARGP, so here's a description of them:
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OPTIONS -- A pointer to a vector of struct argp_option (see below)
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PARSER -- A function to parse a single option, called by argp
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ARGS_DOC -- A string describing how the non-option arguments should look
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DOC -- A descriptive string about this program; if it contains a
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vertical tab character (\v), the part after it will be
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printed *following* the options
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The function PARSER takes the following arguments:
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KEY -- An integer specifying which option this is (taken
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from the KEY field in each struct argp_option), or
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a special key specifying something else; the only
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special keys we use here are ARGP_KEY_ARG, meaning
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a non-option argument, and ARGP_KEY_END, meaning
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that all arguments have been parsed
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ARG -- For an option KEY, the string value of its
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argument, or NULL if it has none
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STATE-- A pointer to a struct argp_state, containing
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various useful information about the parsing state; used here
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are the INPUT field, which reflects the INPUT argument to
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argp_parse, and the ARG_NUM field, which is the number of the
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current non-option argument being parsed
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It should return either 0, meaning success, ARGP_ERR_UNKNOWN, meaning the
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given KEY wasn't recognized, or an errno value indicating some other
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error.
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Note that in this example, main uses a structure to communicate with the
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parse_opt function, a pointer to which it passes in the INPUT argument to
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argp_parse. Of course, it's also possible to use global variables
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instead, but this is somewhat more flexible.
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The OPTIONS field contains a pointer to a vector of struct argp_option's;
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that structure has the following fields (if you assign your option
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structures using array initialization like this example, unspecified
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fields will be defaulted to 0, and need not be specified):
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NAME -- The name of this option's long option (may be zero)
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KEY -- The KEY to pass to the PARSER function when parsing this option,
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*and* the name of this option's short option, if it is a
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printable ascii character
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ARG -- The name of this option's argument, if any
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FLAGS -- Flags describing this option; some of them are:
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OPTION_ARG_OPTIONAL -- The argument to this option is optional
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OPTION_ALIAS -- This option is an alias for the
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previous option
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OPTION_HIDDEN -- Don't show this option in --help output
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DOC -- A documentation string for this option, shown in --help output
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An options vector should be terminated by an option with all fields zero. */
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#include <stdlib.h>
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#include <argp.h>
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const char *argp_program_version =
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"argp-ex3 1.0";
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const char *argp_program_bug_address =
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"<bug-gnu-utils@@gnu.org>";
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/* Program documentation. */
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static char doc[] =
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"Argp example #3 -- a program with options and arguments using argp";
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/* A description of the arguments we accept. */
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static char args_doc[] = "ARG1 ARG2";
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/* The options we understand. */
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static struct argp_option options[] = {
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{"verbose", 'v', 0, 0, "Produce verbose output" },
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{"quiet", 'q', 0, 0, "Don't produce any output" },
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{"silent", 's', 0, OPTION_ALIAS },
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{"output", 'o', "FILE", 0,
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"Output to FILE instead of standard output" },
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{ 0 }
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};
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/* Used by @code{main} to communicate with @code{parse_opt}. */
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struct arguments
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{
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char *args[2]; /* @var{arg1} & @var{arg2} */
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int silent, verbose;
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char *output_file;
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};
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/* Parse a single option. */
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static error_t
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parse_opt (int key, char *arg, struct argp_state *state)
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{
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/* Get the @var{input} argument from @code{argp_parse}, which we
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know is a pointer to our arguments structure. */
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struct arguments *arguments = state->input;
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switch (key)
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{
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case 'q': case 's':
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arguments->silent = 1;
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break;
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case 'v':
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arguments->verbose = 1;
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break;
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case 'o':
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arguments->output_file = arg;
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break;
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case ARGP_KEY_ARG:
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if (state->arg_num >= 2)
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/* Too many arguments. */
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argp_usage (state);
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arguments->args[state->arg_num] = arg;
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break;
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case ARGP_KEY_END:
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if (state->arg_num < 2)
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/* Not enough arguments. */
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argp_usage (state);
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break;
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default:
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return ARGP_ERR_UNKNOWN;
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}
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return 0;
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}
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/* Our argp parser. */
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static struct argp argp = { options, parse_opt, args_doc, doc };
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int
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main (int argc, char **argv)
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{
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struct arguments arguments;
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/* Default values. */
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arguments.silent = 0;
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arguments.verbose = 0;
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arguments.output_file = "-";
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/* Parse our arguments; every option seen by @code{parse_opt} will
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be reflected in @code{arguments}. */
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argp_parse (&argp, argc, argv, 0, 0, &arguments);
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printf ("ARG1 = %s\nARG2 = %s\nOUTPUT_FILE = %s\n"
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"VERBOSE = %s\nSILENT = %s\n",
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arguments.args[0], arguments.args[1],
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arguments.output_file,
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arguments.verbose ? "yes" : "no",
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arguments.silent ? "yes" : "no");
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exit (0);
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}
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