(Unicode C) Check Internet Connectivity

Demonstrates an efficient way to test for Internet connectivity.

Chilkat C/C++ Library Downloads
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#include <C_CkSocketW.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkSocketW socket;
    const wchar_t *targetIp;
    int port;
    BOOL ssl;
    int timeoutMs;

    success = FALSE;

    socket = CkSocketW_Create();
    // 1. Use a reliable Anycast IP. 
    //    8.8.8.8 (Google) or 1.1.1.1 (Cloudflare) are the industry standards.
    targetIp = L"8.8.8.8";

    // 2. Use Port 53 (DNS). 
    //    DNS servers typically listen on TCP Port 53 as well as UDP. 
    //    (Alternatively, use port 443 if you suspect port 53 is blocked).
    port = 53;

    // 3. Disable SSL (0). 
    //    We are not doing a handshake, just a TCP connection.
    ssl = FALSE;

    // 4. Short Timeout (1500ms).
    //    If you can't reach Google in 1.5 seconds, the connection is 
    //    likely too poor for practical use anyway.
    timeoutMs = 1500;

    // Connect
    success = CkSocketW_Connect(socket,targetIp,port,ssl,timeoutMs);
    if (success == FALSE) {
        wprintf(L"%s\n",CkSocketW_lastErrorText(socket));
        CkSocketW_Dispose(socket);
        return;
    }

    CkSocketW_Close(socket,10);

    wprintf(L"We have Internet connectivity.\n");


    CkSocketW_Dispose(socket);

    }