RegisterServiceCtrlHandler

A service calls the RegisterServiceCtrlHandler function to register a function to handle its service control requests.

This function has been superseded by the RegisterServiceCtrlHandlerEx function. A service can use either function, but the new function supports user-defined context data, and the new handler function supports additional extended control codes.

SERVICE_STATUS_HANDLE RegisterServiceCtrlHandler(
  LPCTSTR lpServiceName,             // service name
  LPHANDLER_FUNCTION lpHandlerProc   // handler function
);

Parameters

lpServiceName

[in] Pointer to a null-terminated string that specifies the name of the service run by the calling thread. This is the service name that the service control program specified in the CreateService function when creating the service.

If the service type is SERVICE_WIN32_OWN_PROCESS, the function does not verify that the specified name is valid, because there is only one registered service in the process.

lpHandlerProc

[in] Pointer to the handler function to be registered. For more information, see Handler.

Return Values

If the function succeeds, the return value is a service status handle.

If the function fails, the return value is zero. To get extended error information, call GetLastError.

The following error codes can be set by the service control manager. Other error codes can be set by the registry functions that are called by the service control manager.

Remarks

The ServiceMain function of a new service should immediately call the RegisterServiceCtrlHandler function to register a control handler function with the control dispatcher. This enables the control dispatcher to invoke the specified function when it receives control requests for this service. The threads of the calling process can use the service status handle returned by this function to identify the service in subsequent calls to the SetServiceStatus function.

The RegisterServiceCtrlHandler function must be called before the first SetServiceStatus call because RegisterServiceCtrlHandler returns a service status handle for the caller to use so that no other service can inadvertently set this service status. In addition, the control handler must be in place to receive control requests by the time the service specifies the controls it accepts through the SetServiceStatus function.

When the control handler function is invoked with a control request, it must call SetServiceStatus to notify the service control manager of its current status, regardless of whether the status of the service has changed.

The service status handle does not have to be closed.

Requirements

  Windows NT/2000: Requires Windows NT 3.1 or later.
  Header: Declared in Winsvc.h; include Windows.h.
  Library: Use Advapi32.lib.
  Unicode: Implemented as Unicode and ANSI versions on Windows NT/2000.

See Also

Services Overview, Service Functions, CreateService, Handler, RegisterServiceCtrlHandlerEx, ServiceMain, SetServiceStatus