#include <stdio.h>#include <string.h> #define ERR(s, c) \    if (opterr) {\        char errbuf[2];\        errbuf[0] = (char) c; errbuf[1] = '\n';\        (void) fwrite (argv[0], strlen (argv[0]), 1, stderr);\        (void) fwrite (s, strlen (s), 1, stderr);\        (void) fwrite (errbuf, 2, 1, stderr);\    } int opterr = 1;int optind = 1;int optopt;const char *optarg; #ifdef __STDC__int getopt (int argc, char *argv[], const char *opts)#elseint getopt (argc, argv, opts)int argc;char *argv[];const char *opts;#endif{    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], "--") == 0) {            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); }/* getopt */