argc和argv参数获取函数getopt和optarg

#include
#include
int main(int argc, char *argv[])
{
    int fd;
    int arg;

    while ((arg = getopt(argc, argv, "ps:" )) != EOF) {
        switch (arg) {
            case 'p': {
                int num = 0;

                for (;;) {
                    if ((fd = open_ups()) < 0) {
                        if (num == 0)
                            fprintf(stderr, "no ups!\n");
                        return -1;
                    }
                    num++;
                    printf("[%02d] 0x%04x:0x%04x\n", fd, ups[fd].udev->descriptor.idVendor, ups[fd].udev->descriptor.idProduct);
                }
            } break;
            case 's': {
                printf("%s\n", optarg);
            } break;
            default: break;
        }
    }
}