Programming instructions

Programming Examples
LAN Programming Examples
Chapter 288
posn = strchr(optstring, c); /* DDP */
if (posn == NULL || c == ’:’) {
fprintf(stderr, "%s: unknown option -%c\n", argv[0], c);
return(’?’);
}
posn++;
if (*posn == ’:’) {
if (*scan != ’\0’) {
optarg = scan;
scan = NULL;
} else {
optarg = argv[optind];
optind++;
}
}
return(c);
}