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Diffstat (limited to 'libshouldbeinlibc/argp-ex3.c')
| -rw-r--r-- | libshouldbeinlibc/argp-ex3.c | 140 |
1 files changed, 140 insertions, 0 deletions
diff --git a/libshouldbeinlibc/argp-ex3.c b/libshouldbeinlibc/argp-ex3.c new file mode 100644 index 00000000..a784a646 --- /dev/null +++ b/libshouldbeinlibc/argp-ex3.c @@ -0,0 +1,140 @@ +/* Argp example #3 -- a program with options and arguments using argp */ + +/* This program uses the same features as example 2, and uses options and + arguments. + + We now use the first four fields in ARGP, so here's a description of them: + OPTIONS -- A pointer to a vector of struct argp_option (see below) + PARSER -- A function to parse a single option, called by argp + ARGS_DOC -- A string describing how the non-option arguments should look + DOC -- A descriptive string about this program; if it contains a + vertical tab character (\v), the part after it will be + printed *following* the options + + The function PARSER takes the following arguments: + KEY -- An integer specifying which option this is (taken + from the KEY field in each struct argp_option), or + a special key specifying something else; the only + special keys we use here are ARGP_KEY_ARG, meaning + a non-option argument, and ARGP_KEY_END, meaning + that all argumens have been parsed + ARG -- For an option KEY, the string value of its + argument, or NULL if it has none + STATE-- A pointer to a struct argp_state, containing + various useful information about the parsing state; used here + are the INPUT field, which reflects the INPUT argument to + argp_parse, and the ARG_NUM field, which is the number of the + current non-option argument being parsed + It should return either 0, meaning success, ARGP_ERR_UNKNOWN, meaning the + given KEY wasn't recognized, or an errno value indicating some other + error. + + Note that in this example, main uses a structure to communicate with the + parse_opt function, a pointer to which it passes in the INPUT argument to + argp_parse. Of course, it's also possible to use global variables + instead, but this is somewhat more flexible. + + The OPTIONS field contains a pointer to a vector of struct argp_option's; + that structure has the following fields (if you assign your option + structures using array initialization like this example, unspecified + fields will be defaulted to 0, and need not be specified): + NAME -- The name of this option's long option (may be zero) + KEY -- The KEY to pass to the PARSER function when parsing this option, + *and* the name of this option's short option, if it is a + printable ascii character + ARG -- The name of this option's argument, if any + FLAGS -- Flags describing this option; some of them are: + OPTION_ARG_OPTIONAL -- The argument to this option is optional + OPTION_ALIAS -- This option is an alias for the + previous option + OPTION_HIDDEN -- Don't show this option in --help output + DOC -- A documentation string for this option, shown in --help output + + An options vector should be terminated by an option with all fields zero. */ + +#include <argp.h> + +char *argp_program_version = "argp-ex3 1.0"; +char *argp_program_bug_address = "<bug-gnu-utils@prep.ai.mit.edu>"; + +static char doc[] = + "Argp example #3 -- a program with options and arguments using argp"; +static char args_doc[] = "ARG1 ARG2"; + +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 } +}; + +/* Used by main to communicate with parse_opt. */ +struct arguments +{ + char *args[2]; /* ARG1 & ARG2 */ + int silent, verbose; + char *output_file; +}; + +static error_t +parse_opt (int key, char *arg, struct argp_state *state) +{ + /* Get the INPUT argument from 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 ARGP_KEY_ARG: + if (state->arg_num >= 2) + /* Too many arguments. */ + argp_usage (state); + + arguments->args[state->arg_num] = arg; + + break; + + case ARGP_KEY_END: + if (state->arg_num < 2) + /* Not enough arguments. */ + argp_usage (state); + break; + + default: + return ARGP_ERR_UNKNOWN; + } + return 0; +} + +static struct argp argp = { options, parse_opt, args_doc, doc }; + +int main (int argc, char **argv) +{ + struct arguments arguments; + + /* Default values. */ + arguments.silent = 0; + arguments.verbose = 0; + arguments.output_file = "-"; + + argp_parse (&argp, argc, argv, 0, 0, &arguments); + + printf ("ARG1 = %s\nARG2 = %s\nOUTPUT_FILE = %s\nVERBOSE = %s\nSILENT = %s\n", + arguments.args[0], arguments.args[1], + arguments.output_file, + arguments.verbose ? "yes" : "no", + arguments.silent ? "yes" : "no"); + + exit (0); +} |