为WsCreateServiceHost定义服务端点地址

Question

我正在MSDN中使用HttpCalculatorServiceExample。应在WS_SERVICE_ENDPOINT结构中定义什么端点地址。表达式L"http://+:80/example"对我来说很奇怪。 +:80的含义是什么？我想80是端口号。但为什么+？

int __cdecl wmain(int argc, __in_ecount(argc) wchar_t **argv)
{
    UNREFERENCED_PARAMETER(argc);
    UNREFERENCED_PARAMETER(argv);

    HRESULT hr = NOERROR;
    WS_SERVICE_HOST* host = NULL;
    WS_SERVICE_ENDPOINT serviceEndpoint = {};
    const WS_SERVICE_ENDPOINT* serviceEndpoints[1];
    serviceEndpoints[0] = &serviceEndpoint;

    WS_ERROR* error = NULL;

    WS_SERVICE_ENDPOINT_PROPERTY serviceEndpointProperties[1];
    WS_SERVICE_PROPERTY_CLOSE_CALLBACK closeCallbackProperty = {CloseChannelCallback};
    serviceEndpointProperties[0].id = WS_SERVICE_ENDPOINT_PROPERTY_CLOSE_CHANNEL_CALLBACK;
    serviceEndpointProperties[0].value = &closeCallbackProperty;
    serviceEndpointProperties[0].valueSize = sizeof(closeCallbackProperty);


    // Initialize service endpoint
    serviceEndpoint.address.url.chars = L"http://+:80/example"; // address given as uri
    serviceEndpoint.address.url.length = (ULONG)wcslen(serviceEndpoint.address.url.chars);
    serviceEndpoint.channelBinding = WS_HTTP_CHANNEL_BINDING; // channel binding for the endpoint
    serviceEndpoint.channelType = WS_CHANNEL_TYPE_REPLY; // the channel type
    serviceEndpoint.contract = &calculatorContract;  // the contract
    serviceEndpoint.properties = serviceEndpointProperties;
    serviceEndpoint.propertyCount = WsCountOf(serviceEndpointProperties);

    // Create an error object for storing rich error information
    hr = WsCreateError(
        NULL, 
        0, 
        &error);
    if (FAILED(hr))
    {
        goto Exit;
    }
    // Create Event object for closing the server
    closeServer = CreateEvent(
        NULL, 
        TRUE, 
        FALSE, 
        NULL);
    if (closeServer == NULL)
    {
        hr = HRESULT_FROM_WIN32(GetLastError());
        goto Exit;
    }   
    // Creating a service host
    hr = WsCreateServiceHost(
        serviceEndpoints, 
        1, 
        NULL, 
        0, 
        &host, 
        error);
    if (FAILED(hr))
    {
        goto Exit;
    }
    // WsOpenServiceHost to start the listeners in the service host 
    hr = WsOpenServiceHost(
        host, 
        NULL, 
        error);
    if (FAILED(hr))
    {

        goto Exit;
    }
    WaitForSingleObject(closeServer, INFINITE);
    // Close the service host
    hr = WsCloseServiceHost(host, NULL, error);
    if (FAILED(hr))
    {
        goto Exit;
    }

Exit:
    if (FAILED(hr))
    {
        // Print out the error
        PrintError(hr, error);
    }
    fflush(
        stdout);
    if (host != NULL)
    {
        WsFreeServiceHost(host);
    }


    if (error != NULL)
    {
        WsFreeError(error);
    }
    if (closeServer != NULL)
    {
        CloseHandle(closeServer);
    }
    fflush(stdout);
    return SUCCEEDED(hr) ? 0 : -1;
}