ControlService function (winsvc.h)
Sends a control code to a service.
To specify additional information when stopping a service, use the ControlServiceEx function.
BOOL ControlService( SC_HANDLE hService, DWORD dwControl, LPSERVICE_STATUS lpServiceStatus );
This parameter can be one of the following control codes.
This value can also be a user-defined control code, as described in the following table.
||The service defines the action associated with the control code. The hService handle must have the SERVICE_USER_DEFINED_CONTROL access right.|
A pointer to a SERVICE_STATUS structure that receives the latest service status information. The information returned reflects the most recent status that the service reported to the service control manager.
The service control manager fills in the structure only when GetLastError returns one of the following error codes: NO_ERROR, ERROR_INVALID_SERVICE_CONTROL, ERROR_SERVICE_CANNOT_ACCEPT_CTRL, or ERROR_SERVICE_NOT_ACTIVE. Otherwise, the structure is not filled in.
If the function succeeds, the return value is nonzero.
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.
||The handle does not have the required access right.|
||The service cannot be stopped because other running services are dependent on it.|
||The specified handle was not obtained using CreateService or OpenService, or the handle is no longer valid.|
||The requested control code is undefined.|
||The requested control code is not valid, or it is unacceptable to the service.|
||The requested control code cannot be sent to the service because the state of the service is SERVICE_STOPPED, SERVICE_START_PENDING, or SERVICE_STOP_PENDING.|
||The service has not been started.|
||The process for the service was started, but it did not call StartServiceCtrlDispatcher, or the thread that called StartServiceCtrlDispatcher may be blocked in a control handler function.|
||The system is shutting down.|
The ControlService function asks the Service Control Manager (SCM) to send the requested control code to the service. The SCM sends the code if the service has specified that it will accept the code, and is in a state in which a control code can be sent to it.
The SCM processes service control notifications in a serial fashion—it will wait for one service to complete processing a service control notification before sending the next one. Because of this, a call to ControlService will block for 30 seconds if any service is busy handling a control code. If the busy service still has not returned from its handler function when the timeout expires, ControlService fails with ERROR_SERVICE_REQUEST_TIMEOUT.
To stop and start a service requires a security descriptor that allows you to do so. The default security descriptor allows the LocalSystem account, and members of the Administrators and Power Users groups to stop and start services. To change the security descriptor of a service, see Modifying the DACL for a Service.
The QueryServiceStatusEx function returns a SERVICE_STATUS_PROCESS structure whose dwCurrentState and dwControlsAccepted members indicate the current state and controls accepted by a running service. All running services accept the SERVICE_CONTROL_INTERROGATE control code by default. Drivers do not accept control codes other than SERVICE_CONTROL_STOP and SERVICE_CONTROL_INTERROGATE. Each service specifies the other control codes that it accepts when it calls the SetServiceStatus function to report its status. A service should always accept these codes when it is running, no matter what it is doing.
The following table shows the action of the SCM in each of the possible service states.
|Service state||Stop||Other controls|
For an example, see Stopping a Service.
|Minimum supported client||Windows XP [desktop apps only]|
|Minimum supported server||Windows Server 2003 [desktop apps only]|
|Header||winsvc.h (include Windows.h)|