Function _getopt_internal

lib/getopt.c:300–694

(argc, argv, optstring, longopts, longind, long_only)

   long-named options.  */

int
_getopt_internal(argc, argv, optstring, longopts, longind, long_only)
int argc;
char *const *argv;
const char *optstring;
const struct option *longopts;
int *longind;
int long_only;
{
    optarg = 0;

    /* Initialize the internal data when the first call is made.
       Start processing options with ARGV-element 1 (since ARGV-element 0
       is the program name); the sequence of previously skipped
       non-option ARGV-elements is empty.  */

    if (optind == 0)
    {
        first_nonopt = last_nonopt = optind = 1;

        nextchar = NULL;

        /* Determine how to handle the ordering of options and nonoptions.  */

        if (optstring[0] == '-')
        {
            ordering = RETURN_IN_ORDER;
            ++optstring;
        }
        else if (optstring[0] == '+')
        {
            ordering = REQUIRE_ORDER;
            ++optstring;
        }
        else if (getenv("POSIXLY_CORRECT") != NULL)
        {
            ordering = REQUIRE_ORDER;
        }
        else
        {
            ordering = PERMUTE;
        }
    }

    if (nextchar == NULL || *nextchar == '\0')
    {
        if (ordering == PERMUTE)
        {
            /* If we have just processed some options following some non-options,
               exchange them so that the options come first.  */

            if (first_nonopt != last_nonopt && last_nonopt != optind)
            {
                exchange((char **) argv);
            }
            else if (last_nonopt != optind)
            {
                first_nonopt = optind;