这程序啥意思?望各位教教小弟,不甚感激。
char *optarg; /* Global argument pointer. */
int optind = 0; /* Global argv index. */
static char *scan = NULL; /* Private scan pointer. */
extern char *strchr();
//===================================================
//
//===================================================
int getopt(int argc, char **argv, char *optstring) {
register char c;
register char *place;
optarg = NULL;
if (scan == NULL || *scan == '\0') {
if (optind == 0)
optind++;
if (optind >= argc || argv[optind][0] != '-' || argv[optind][1] == '\0')
return(EOF);
if (strcmp(argv[optind], "--")==0) {
optind++;
return(EOF);
}
scan = argv[optind]+1;
optind++;
}
c = *scan++;
place = strchr(optstring, c);
if (place == NULL || c == ':') {
fprintf(stderr, "%s: unknown option -%c\n", argv[0], c);
return('?');
}
place++;
if (*place == ':') {
if (*scan != '\0') {
optarg = scan;
scan = NULL;
} else {
optarg = argv[optind];
optind++;
}
}
return(c);
}