ipv6過審函數

int _ResolveIPv4Address(const char* ipv4_str, char* buffer, int bufferSize)
{
    struct addrinfo hints, *res;
    
    memset(&hints, 0, sizeof(hints));
    hints.ai_family = PF_UNSPEC;
    hints.ai_socktype = SOCK_STREAM;
    hints.ai_flags = AI_DEFAULT;
    
    int error = getaddrinfo(ipv4_str, "http", &hints, &res);
    
    if (error)
    {
        /*NOTREACHED*/
        return error;
    }
    
    // get the first
    if (res->ai_family == AF_INET6)
    {
        // get ipv6 address
        struct sockaddr_in6* ipv6 = (struct sockaddr_in6*)res->ai_addr;
        inet_ntop(AF_INET6, &ipv6->sin6_addr, buffer, bufferSize);
    }
    else
    {
        // get ipv4 address
        struct sockaddr_in* ipv4 = (struct sockaddr_in*)res->ai_addr;
        inet_ntop(AF_INET, &ipv4->sin_addr, buffer, bufferSize);
    }
    
    freeaddrinfo(res);
    return 0;
}