getopt_long.c File Reference

getopt_long - Definition More...

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include "getopt_long.h"

Functions
int	getopt_long (int argc, char *const argv[], const char *optstring, const struct option *longopts, int *longindex)
	Parse long options - BSD style.
Variables
int	optind = 1
	option parsing last error
int	optopt
	index of option to process in argv
char *	optarg
	current option
int	optreset
	argument of current option

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Detailed Description

Author:

Andrea Vedaldi

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Function Documentation

int getopt_long	(	int	argc,
		char *const	argv[],
		const char *	optstring,
		const struct option *	longopts,
		int *	longindex
	)

Parameters:

	argc
	argv
	optstring	abbreviations of
	longopts	list of long options.
	longindex	index of current option in longopts.

This function extract long and short options from the argument list argv of argc entries.

A short options sequence is introduced by a singe dash -. Each short option is described by a signle character int the optstring, possiblily followed by a : character to denote a (mandatory) argument of the short option. A short option with an argument cannot appear in the middle of a short option sequence, but only at the end.

A long option is introduced by a double dash --. Each long option is described by an instace of the option structure in the longopts table (the last entry must be filled with zeroes to denote the end).

Returns:

the code of the next option. Illegal options and mising arguments cause the function to skip the option and return '?'. If opterr is true (default), the function prints an error message to stderr. Finally, if optstring has a leading :, then error messages are supporessed and a missing argument causes : to be returned.

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