source: git/src/getopt.c @ 2c52d8e

#include <stdio.h>
#include <string.h>

#define ERR(_s, _c) { if (opterr) fprintf (stderr, "%s%c\n", argv[0], _s, _c);}

int     opterr = 1;
int     optind = 1;
int     optopt;
char    *optarg;

int getopt(int argc, char **argv, char *opts)
{
        static int sp = 1;
        int c;
        char *cp;

        if(sp == 1)
                if(optind >= argc ||
                   argv[optind][0] != '-' || argv[optind][1] == '\0')
                        return(EOF);
                else if(strcmp(argv[optind], "--") == NULL) {
                        optind++;
                        return(EOF);
                }
        optopt = c = argv[optind][sp];
        if(c == ':' || (cp=strchr(opts, c)) == NULL) {
                ERR(": illegal option -- ", c);
                if(argv[optind][++sp] == '\0') {
                        optind++;
                        sp = 1;
                }
                return('?');
        }
        if(*++cp == ':') {
                if(argv[optind][sp+1] != '\0')
                        optarg = &argv[optind++][sp+1];
                else if(++optind >= argc) {
                        ERR(": option requires an argument -- ", c);
                        sp = 1;
                        return('?');
                } else
                        optarg = argv[optind++];
                sp = 1;
        } else {
                if(argv[optind][++sp] == '\0') {
                        sp = 1;
                        optind++;
                }
                optarg = NULL;
        }
        return(c);
}