写一个ServiceMain函数

#define SVCNAME TEXT("SvcName")SERVICE_STATUS gSvcStatus; SERVICE_STATUS_HANDLE gSvcStatusHandle; HANDLE ghSvcStopEvent = NULL;//// Purpose: //   Entry point for the service//// Parameters://   dwArgc - Number of arguments in the lpszArgv array//   lpszArgv - Array of strings. The first string is the name of//     the service and subsequent strings are passed by the process//     that called the StartService function to start the service.// // Return value://   None.//VOID WINAPI SvcMain( DWORD dwArgc, LPTSTR *lpszArgv ){    // Register the handler function for the service    gSvcStatusHandle = RegisterServiceCtrlHandler(         SVCNAME,         SvcCtrlHandler);    if( !gSvcStatusHandle )    {         SvcReportEvent(TEXT("RegisterServiceCtrlHandler"));         return;     }     // These SERVICE_STATUS members remain as set here    gSvcStatus.dwServiceType = SERVICE_WIN32_OWN_PROCESS;     gSvcStatus.dwServiceSpecificExitCode = 0;        // Report initial status to the SCM    ReportSvcStatus( SERVICE_START_PENDING, NO_ERROR, 3000 );    // Perform service-specific initialization and work.    SvcInit( dwArgc, lpszArgv );}//// Purpose: //   The service code//// Parameters://   dwArgc - Number of arguments in the lpszArgv array//   lpszArgv - Array of strings. The first string is the name of//     the service and subsequent strings are passed by the process//     that called the StartService function to start the service.// // Return value://   None//VOID SvcInit( DWORD dwArgc, LPTSTR *lpszArgv){    // TO_DO: Declare and set any required variables.    //   Be sure to periodically call ReportSvcStatus() with     //   SERVICE_START_PENDING. If initialization fails, call    //   ReportSvcStatus with SERVICE_STOPPED.    // Create an event. The control handler function, SvcCtrlHandler,    // signals this event when it receives the stop control code.    ghSvcStopEvent = CreateEvent(                         NULL,    // default security attributes                         TRUE,    // manual reset event                         FALSE,   // not signaled                         NULL);   // no name    if ( ghSvcStopEvent == NULL)    {        ReportSvcStatus( SERVICE_STOPPED, NO_ERROR, 0 );        return;    }    // Report running status when initialization is complete.    ReportSvcStatus( SERVICE_RUNNING, NO_ERROR, 0 );    // TO_DO: Perform work until service stops.    while(1)    {        // Check whether to stop the service.        WaitForSingleObject(ghSvcStopEvent, INFINITE);        ReportSvcStatus( SERVICE_STOPPED, NO_ERROR, 0 );        return;    }}//// Purpose: //   Sets the current service status and reports it to the SCM.//// Parameters://   dwCurrentState - The current state (see SERVICE_STATUS)//   dwWin32ExitCode - The system error code//   dwWaitHint - Estimated time for pending operation, //     in milliseconds// // Return value://   None//VOID ReportSvcStatus( DWORD dwCurrentState,                      DWORD dwWin32ExitCode,                      DWORD dwWaitHint){    static DWORD dwCheckPoint = 1;    // Fill in the SERVICE_STATUS structure.    gSvcStatus.dwCurrentState = dwCurrentState;    gSvcStatus.dwWin32ExitCode = dwWin32ExitCode;    gSvcStatus.dwWaitHint = dwWaitHint;    if (dwCurrentState == SERVICE_START_PENDING)        gSvcStatus.dwControlsAccepted = 0;    else gSvcStatus.dwControlsAccepted = SERVICE_ACCEPT_STOP;    if ( (dwCurrentState == SERVICE_RUNNING) ||           (dwCurrentState == SERVICE_STOPPED) )        gSvcStatus.dwCheckPoint = 0;    else gSvcStatus.dwCheckPoint = dwCheckPoint++;    // Report the status of the service to the SCM.    SetServiceStatus( gSvcStatusHandle, &gSvcStatus );}

上面例子中的SvcMain函数就是服务实例中的ServiceMain函数。SvcMain可以main函数的方式来访问服务的命令行参数。第一个参数包含要传入到服务中的第二个参数的数量。至少有一个参数。第二个参数是一个指向字符串指针数组的指针。数组中的第一项为服务名。

SvcMain函数首先调用RegisterServiceCtrlHandler函数来注册SvcCtrlHandler函数作为服务的Handler函数，然后开始初始化。RegisterSreviceCtrlHandler是在ServiceMain中第一个必须返回成功的函数，之后服务能够使用该函数返回的状态去调用SetServiceStatus函数设置状态，若发生错误，则状态设为SERVICE_STOPPED。

下一步，SvcMain函数调用ReportSvcStatus函数来指定它的初始状态为SERVICE_START_PENDING。若服务处在这种状态中，将无法接收控制命令。为了简化服务逻辑，建议在初始化操作时，服务不接收任何控制命令。

样例的初始化函数SvcInit，是一个很简单的例子。它不会处理复杂的初始化任务，比如创建额外线程等。它创建一个事件：服务控制处理程序能够发信号让服务停止，随后调用ReportSvcStatus预示服务已经进入SERVICE_RUNNING状态。此时，服务已经完成初始化并准备接收控制命令。为了最好的系统性能，在25~100ms内应用程序应该进入运行状态。

由于该实例服务没有完成任何实际任务，SvcInit仅仅通过调用WaitForSingleObject来等待服务停止事件触发，调用ReportSvcStatus来预示服务已经进入SERVICE_STOPPED状态，并返回。（注意函数返回很重要，而不应该去调用ExitThread函数，由于返回会为之前参数创建的内存做清理工作）。可通过使用函数RegisterWaitForSingleObject来做额外的清理任务而不是用WaitForSingleObject。运行ServiceMain函数的线程终止，但是服务仍然在继续。当服务控制处理函数触发事件时，线程池中的线程执行回调来处理额外的清理工作，包括设置状态为SERVICE_STOPPED。

注意该实例使用SvcReportEvent来写错误事件到事件log。

参考网址：

https://msdn.microsoft.com/en-us/library/windows/desktop/ms687414(v=vs.85).aspx