CODEWITHSUNDEEP
c++visual-studio-2013udp
Yoda
Yoda

Reputation: 18068

Sending over UDP by Visual C++ get lot of unresolved external symbol __imp__sendto@24

I have installed Visual Studio 2013 Ultimate. I tried this code to send anything by UDP(it's 15th or maybe latter code I try) and I get a bunch of weird errors. What do I lack in the project?

#include "stdafx.h"
#include <iostream>
#include <winsock2.h>

using namespace std;

int main()
{
    //init
    int server_length;
    int port = 123;
    const int STRLEN = 256;
    char recMessage[STRLEN];
    char sendMessage[STRLEN];
    char *sendMes = "SERVER READY";
    WSADATA wsaData;
    SOCKET mySocket;
    SOCKET myBackup;
    SOCKET acceptSocket;
    sockaddr_in myAddress;

    //create socket
    if (WSAStartup(MAKEWORD(2, 2), &wsaData) != NO_ERROR)
    {
        cerr << "Socket Initialization: Error with WSAStartup\n";
        system("pause");
        WSACleanup();
        exit(10);
    }

    mySocket = socket(AF_INET, SOCK_DGRAM, 0);
    if (mySocket == INVALID_SOCKET)
    {
        cerr << "Socket Initialization: Error creating socket" << endl;
        system("pause");
        WSACleanup();
        exit(11);
    }

    myBackup = mySocket;

    //bind
    myAddress.sin_family = AF_INET;
    myAddress.sin_addr.s_addr = inet_addr("0.0.0.0");
    myAddress.sin_port = htons(port);

    if (bind(mySocket, (SOCKADDR*)&myAddress, sizeof(myAddress)) == SOCKET_ERROR)
    {
        cerr << "ServerSocket: Failed to connect\n";
        system("pause");
        WSACleanup();
        exit(14);
    }

    cout << endl;
    while (1)
    {
        server_length = sizeof(struct sockaddr_in);
        recvfrom(mySocket, recMessage, STRLEN, 0, (SOCKADDR*)&myAddress, &server_length);
        cout << recMessage << endl;
        sendto(mySocket, sendMes, strlen(sendMes), 0, (SOCKADDR*)&myAddress, server_length);

    }

    return 0;
}

Error   11  error LNK1120: 8 unresolved externals   c:\users\r\documents\visual studio 2013\Projects\ConsoleApplication17\Debug\ConsoleApplication17.exe    1   1   ConsoleApplication17
Error   3   error LNK2019: unresolved external symbol __imp__bind@12 referenced in function _main   c:\Users\R\documents\visual studio 2013\Projects\ConsoleApplication17\ConsoleApplication17\ConsoleApplication17.obj ConsoleApplication17
Error   4   error LNK2019: unresolved external symbol __imp__htons@4 referenced in function _main   c:\Users\R\documents\visual studio 2013\Projects\ConsoleApplication17\ConsoleApplication17\ConsoleApplication17.obj ConsoleApplication17
Error   5   error LNK2019: unresolved external symbol __imp__inet_addr@4 referenced in function _main   c:\Users\R\documents\visual studio 2013\Projects\ConsoleApplication17\ConsoleApplication17\ConsoleApplication17.obj ConsoleApplication17
Error   6   error LNK2019: unresolved external symbol __imp__recvfrom@24 referenced in function _main   c:\Users\R\documents\visual studio 2013\Projects\ConsoleApplication17\ConsoleApplication17\ConsoleApplication17.obj ConsoleApplication17
Error   7   error LNK2019: unresolved external symbol __imp__sendto@24 referenced in function _main c:\Users\R\documents\visual studio 2013\Projects\ConsoleApplication17\ConsoleApplication17\ConsoleApplication17.obj ConsoleApplication17
Error   8   error LNK2019: unresolved external symbol __imp__socket@12 referenced in function _main c:\Users\R\documents\visual studio 2013\Projects\ConsoleApplication17\ConsoleApplication17\ConsoleApplication17.obj ConsoleApplication17
Error   10  error LNK2019: unresolved external symbol __imp__WSACleanup@0 referenced in function _main  c:\Users\R\documents\visual studio 2013\Projects\ConsoleApplication17\ConsoleApplication17\ConsoleApplication17.obj ConsoleApplication17
Error   9   error LNK2019: unresolved external symbol __imp__WSAStartup@8 referenced in function _main  c:\Users\R\documents\visual studio 2013\Projects\ConsoleApplication17\ConsoleApplication17\ConsoleApplication17.obj ConsoleApplication17
Warning 2   warning C4101: 'acceptSocket' : unreferenced local variable c:\users\r\documents\visual studio 2013\projects\consoleapplication17\consoleapplication17\consoleapplication17.cpp 21  1   ConsoleApplication17
Warning 1   warning C4101: 'sendMessage' : unreferenced local variable  c:\users\r\documents\visual studio 2013\projects\consoleapplication17\consoleapplication17\consoleapplication17.cpp 16  1   ConsoleApplication17

Upvotes: 0

Views: 2308

Answers (1)

Maurice
Maurice

Reputation: 610

stdafx.h needs to be included before anything else or the winsock2.h and iostream includes will be ignored.

stdafx.h is a file, generated by Microsoft Visual Studio IDE wizards, that describes both standard system and project specific include files that are used frequently but hardly ever change.

Compatible compilers (for example, Visual C++ 6.0 and newer) will precompile this file to reduce overall compile times. Visual C++ will not compile anything before the #include "stdafx.h" in the source file, unless the compile option /Yu'stdafx.h' is unchecked (by default); it assumes all code in the source up to and including that line is already compiled.

(http://en.wikipedia.org/wiki/Precompiled_header)

EDIT: You need to include the library for winsock called Ws2_32.lib, you can do so by adding #pragma comment(lib, "Ws2_32.lib"). You can add libraries in the IDE if you want it to work on multiple IDEs.

(http://msdn.microsoft.com/en-us/library/windows/desktop/ms737629%28v=vs.85%29.aspx)

Upvotes: 3

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