Send email with C/C++ [on hold]

I don't know what to declare MBICON_ERROR or sendToSock in this script. I'm trying to get the program to send me messages and text file attachments through email from the desktop silently.

#include <winsock2.h>
#include <ws2tcpip.h>

#pragma comment(lib, "Ws2_32.lib")

#include <string.h>
#include <string>
using std::string;

static void InitializeWinSock()
{
    WSADATA wsaData;
    int iResult = WSAStartup(MAKEWORD(2, 2), &wsaData);
    if (iResult != 0) {
        MessageBox(NULL, "Unable to initialize WinSock", "Initialization Error", MBICON_ERROR | MB_OK);
        exit(0);
    }
}

SOCKET openSocketToServer(const std::string& addr, int port)
{
    // open socket ...
}

#define MAIL_SERVER_IP "127.0.0.1"
#define MAIL_SERVER_PORT 25

void sendMail(const string& mailTo, const string& mailFrom, const string& subject, const string& body)
{
    InitializeWinSock();

    SOCKET servSock = openSocketToServer(MAIL_SERVER_IP, MAIL_SERVER_PORT);

    sendToSock(servSock, "HELO sender", "");
    sendToSock(servSock, "MAIL FROM: ", mailFrom.c_str());
    sendToSock(servSock, "RCPT TO: ", mailTo.c_str());
    sendToSock(servSock, "DATA", "");
    sendToSock(servSock, "From: ", mailFrom.c_str());
    sendToSock(servSock, "To: ", mailTo.c_str());
    sendToSock(servSock, "Subject: ", subject);
    sendToSock(servSock, "", ""); // blank line.
    sendToSock(servSock, body.c_str(), "");
    sendToSock(servSock, ".", "");
    sendToSock(servSock, "quit", "");
}