CODEWITHSUNDEEP
c++getopt
Dmitriy Savin
Dmitriy Savin

Reputation: 143

Optarg is alway null

Optarg is always null. Application crashes. 

static const char* const short_options = "a:h:p";
static const struct option long_options[] =
{
    { "address",    1, NULL, 'a' },
    { "help",       0, NULL, 'h' },
    { "port",       1, NULL, 'p' }
};

I tried to add null string to the long_options, but it did not help.

static const struct option long_options[] =
{
    { "address",    1, NULL, 'a' },
    { "help",       0, NULL, 'h' },
    { "port",       1, NULL, 'p' },
    {0,             0, NULL,  0 }
};

but it did not help.

There is example of the optarg using. I use optarg with the same way, but get null.

do {
        nextOption = getopt_long(argc, argv, short_options, long_options, NULL);
        switch (nextOption)
        {
        case 'a':
        {
            //do something
        }
            break;
        case 'h':
            printf(usage_template);
            exit(0);
        case 'p':
        {
            long value;
            char* end;
            value = strtol(optarg, &end, 10);//OPTARG IS NULL
            if (*end != '\0')
            {
                printf(usage_template);
            }
            port = (uint16_t)htons(value);
        }
            break;
        case '?':
            printf(usage_template);
            exit(0);
        case -1:
            break;
        default:
            exit(0);
        }
    } while (nextOption != -1);

Can anybody help me with this issue?

Upvotes: 1

Views: 1021

Answers (1)

c_dubs
c_dubs

Reputation: 360

It looks like your "p" option isn't followed by a colon, so getopt isn't expecting it to have an argument.

Upvotes: 6

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