getopt_long.c

#include <getopt.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <limits.h>

void
version(void)
{
    printf("HTTPMon 1.0.0\n");
}

void
usage(void)
{
    printf("usage:\n");
    printf("-v/--version\tdisplay program version\n");
    printf("-h/--help\tdisplay this help\n");
    printf("-q/--request-if\tinterface of incoming HTTP requests\n");
    printf("-s/--response-if\tinterface of outgoing HTTP responses\n");
}

int
main(int argc, char** argv)
{
    int ch;
    const char* request_if = NULL;
    const char* response_if = NULL;
    char* tmp;
    unsigned long worker_count = 1;

    struct option longopts[] = {
        {"version",         0,  NULL,   'v'},
        {"help",            0,  NULL,   'h'},
        {"request-if",      1,  NULL,   'q'},
        {"response-if",     1,  NULL,   's'},
        {"worker-count",    1,  NULL,   'w'},
        {NULL,              0,  NULL,   0},
    };

    while ((ch = getopt_long(argc, argv, "hvq:s:w:", longopts, NULL)) != -1) {
        switch (ch) {
        case 'v':
            version();
            exit(0);
        case 'h':
            usage();
            exit(0);
        case 'q':
            request_if = optarg;
            break;
        case 's':
            response_if = optarg;
            break;
        case 'w':
            worker_count = strtoul(optarg, &tmp, 10);
            if ((worker_count==ULONG_MAX && errno==ERANGE) /* overflow */
                    || *tmp!=0) { /* or trash characters */
                fprintf(stderr, "%s: error parsing worker count: %s\n",
                        argv[0], optarg);
                usage();
                exit(1);
            }
            break;
        case '?':
        default:
            usage();
            exit(1);
        }
    }

    if (request_if==NULL) {
        fprintf(stderr, "%s: missing required argument -q/--request-if\n",
                argv[0]);
        usage();
        exit(1);
    }

    if (response_if==NULL) {
        fprintf(stderr, "%s: missing required argument -s/--response-if\n",
                argv[0]);
        usage();
        exit(1);
    }

    version();
    printf("request interface: %s\n", request_if);
    printf("response interface: %s\n", response_if);
    printf("worker count: %lu\n", worker_count);

    return 0;
}