Simple command line tool in C which uses getopt_long

speak.c

#include <stdio.h>
#include <ctype.h>
#include <stdbool.h>
#include <stdlib.h>
#include <getopt.h>
#include <string.h>

static struct config {
    bool yell;
} cfg;

static struct option long_options[] = {
    {"help", no_argument, NULL, 'h'},
    {"yell", no_argument, NULL, 'y'}
};

static int parse_args(struct config *cfg, int argc, char *argv[]);

static void help() {
    printf("Usage: speak [options]                     \n"
           "    -y, --yell        Echo the input loudly\n"
           "    -h, --help        Show this help       \n");
}

int main(int argc, char *argv[]) {    
    if (parse_args(&cfg, argc, argv)) {
        help();
        exit(1);
    }

    int c;

    while ((c = fgetc(stdin)) != EOF) {
        if (cfg.yell) {
            putc(toupper(c), stdout);
        } else {
            putc(c, stdout);
        }
    }
    return 0;
}

static int parse_args(struct config *cfg, int argc, char *argv[]) {
    int c;
    memset(cfg, 0, sizeof(struct config));
    while ((c = getopt_long(argc, argv, "hy", long_options, NULL)) != -1) {
        switch (c) {
            case 'h':
                help();
                exit(0);
                break;
            case 'y':
                cfg->yell = true;
                break;
            default:
                return -1;
                break;
        }
    }
    return 0;
}