console app option in C

console-app-args.c

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

#define OPT1 "Operation1"
#define OPT2 "Operation2"

struct global_args_t {
    const char *program_name;
    const char *config_file;
    const char *operation_name;
    int verbose;
} _args;

void print_usage(FILE* stream, int exit_code) {
    fprintf(stream, "Usage: %s -o <operation name> [other options] \n", _args.program_name);
    fprintf(stream,
            "  -h  --help               Display usage information.\n"
            "  -o  --operation name     Run operation name (\"" OPT1 "\", \"" OPT2 "\").\n"
            "  -c  --config filename    Run with configuration file.\n"
            "  -v  --verbose            Print verbose messages.\n");
    exit(exit_code);
}

void select_option(int argc, char* argv[]) {

    int next_option;
    const char* const short_options = "ho:c:v";
    const struct option long_options[] = {
        { "help", no_argument, NULL, 'h'},
        { "operation", required_argument, NULL, 'o'},
        { "configure", required_argument, NULL, 'c'},
        { "verbose", no_argument, NULL, 'v'},
        { NULL, no_argument, NULL, 0}
    };

    _args.config_file = NULL;
    _args.operation_name = NULL;
    _args.verbose = 0;
    _args.program_name = argv[0];

    do {
        next_option = getopt_long(argc, argv, short_options, long_options, NULL);
        switch (next_option) {
            case 'o':
                _args.operation_name = optarg;
                break;
            case 'c':
                _args.config_file = optarg;
                break;
            case 'v':
                _args.verbose = 1;
                break;
            case 'h':
            case '?':
                print_usage(stdout, 0);
            case -1: /* Done with options.  */
                break;
            default: /* Something else: unexpected.  */
                exit(EXIT_FAILURE);
        }
    } while (next_option != -1);

    if (argc < 2 || _args.operation_name == NULL) {
        print_usage(stdout, 0);
    }

    // remained arguments
    if (_args.verbose) {
        for (int i = optind; i < argc; ++i) {
            printf("Argument: %s\n", argv[i]);
        }
    }

    
    if(strcmp(_args.operation_name, OPT1) == 0) {
        printf("operation: %s\n",_args.operation_name);
    } else if(strcmp(_args.operation_name, OPT2) == 0) {
        printf("operation: %s\n",_args.operation_name);
    } else {
        printf("Unknown operation\n");
        print_usage(stdout, 0);
    }
    
}

int main(int argc, char* argv[]) {
    select_option(argc, argv);
}