udp.cpp

//
// Created by AERO on 12/15/2020.
//

#pragma comment(lib, "Ws2_32.lib")
#include <errno.h>
#include <stdlib.h>
#include <iostream>
#include <winsock2.h>
#include <ws2tcpip.h>
#include <opencv2/core.hpp>

using namespace cv;


int resolvehelper(const char* hostname, int family, const char* service, sockaddr_storage* pAddr)
{
    int result;
    addrinfo* result_list = NULL;
    addrinfo hints = {};
    hints.ai_family = family;
    hints.ai_socktype = SOCK_DGRAM; // without this flag, getaddrinfo will return 3x the number of addresses (one for each socket type).
    result = getaddrinfo(hostname, service, &hints, &result_list);
    if (result == 0)
    {
        //ASSERT(result_list->ai_addrlen <= sizeof(sockaddr_in));
        memcpy(pAddr, result_list->ai_addr, result_list->ai_addrlen);
        freeaddrinfo(result_list);
    }

    return result;
}


int send_to(String str)
{
    int result = 0;
    SOCKET sock = socket(AF_INET, SOCK_DGRAM, 0);

    char szIP[100];

    sockaddr_in addrListen = {}; // zero-int, sin_port is 0, which picks a random port for bind.
    addrListen.sin_family = AF_INET;
    result = bind(sock, (sockaddr*)&addrListen, sizeof(addrListen));
    if (result == -1)
    {
        int lasterror = errno;
        std::cout << "error: " << lasterror;
        exit(1);
    }


    sockaddr_storage addrDest = {};
    result = resolvehelper("192.168.0.4", AF_INET, "9000", &addrDest);
    if (result != 0)
    {
        int lasterror = errno;
        std::cout << "error: " << lasterror;
        exit(1);
    }

    const char* msg = str.c_str();
    size_t msg_length = strlen(msg);

    result = sendto(sock, msg, msg_length, 0, (sockaddr*)&addrDest, sizeof(addrDest));

    std::cout << result << " bytes sent" << std::endl;

    return 0;

}