getopt实现用户参数

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/unistd.h>

int main(int argc, char * argv[])
{
        int opt;
        char * name = NULL;
        while (-1 != (opt = getopt(argc, argv, "n:lm"))) {
                switch (opt) {
                        case 'n':
                        name = strdup(optarg);
                        if (NULL == name) {
                                fprintf(stderr, "memory is exhausted!\n");
                                exit(1);
                        }
                        break;
                        case 'l':
                        case 'm':
                        break;
                        default:
                        fprintf(stderr, "usage: %s [options] [optarg]\n", argv[0]);
                        break;
                }
        }

        if (name) {
                fprintf(stdout, "the optarg is: %s\n", name);
                free(name);
        }

        return 0;
}
格式化字符串中字符‘：’前需要带选项参数