ControlService

The ControlService function sends a control code to a Win32-based service.

BOOL ControlService(
  SC_HANDLE hService,  // handle to service
  DWORD dwControl,     // control code
  LPSERVICE_STATUS lpServiceStatus 
                       // pointer to service status structure
);

Parameters

hService

Handle to the service. This handle is returned by the OpenService or CreateService function. The access required for this handle depends on the dwControl code requested.

dwControl

Specifies the requested control code. This value can be one of the standard control codes in the following table:

Value	Meaning

SERVICE_CONTROL_STOP	Requests the service to stop. The hService handle must have SERVICE_STOP access.
SERVICE_CONTROL_PAUSE	Requests the service to pause. The hService handle must have SERVICE_PAUSE_CONTINUE access.
SERVICE_CONTROL_ CONTINUE	Requests the paused service to resume. The hService handle must have SERVICE_PAUSE_CONTINUE access.
SERVICE_CONTROL_ INTERROGATE	Requests the service to update immediately its current status information to the service control manager. The hService handle must have SERVICE_INTERROGATE access.
SERVICE_CONTROL_ SHUTDOWN	The ControlService function fails if this control code is specified.

This value can also be a user-defined control code, as described in the following table:

Value Meaning

Range 128 to 255. The service defines the action associated with the control code. The hService handle must have SERVICE_USER_DEFINED_CONTROL access.

lpServiceStatus

Value	Meaning
Range 128 to 255.	The service defines the action associated with the control code. The hService handle must have SERVICE_USER_DEFINED_CONTROL access.

Pointer to a SERVICE_STATUS structure to receive the latest service status information. The information returned reflects the most recent status that the service reported to the service control manager.

Return Values

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.

Errors

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.

Value	Meaning
ERROR_ACCESS_DENIED
	The specified handle was not opened with the necessary access.
ERROR_DEPENDENT_SERVICES_RUNNING
	The service cannot be stopped because other running services are dependent on it.
ERROR_INVALID_SERVICE_CONTROL
	The requested control code is not valid, or it is unacceptable to the service.
ERROR_SERVICE_CANNOT_ACCEPT_CTRL
	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.
ERROR_SERVICE_NOT_ACTIVE
	The service has not been started.
ERROR_SERVICE_REQUEST_TIMEOUT
	The service did not respond to the start request in a timely fashion.

Remarks

The ControlService function asks the service control manager to send the requested control code to the service. The service control manager sends the code if the service accepts the control and if the service is in a state in which a control can be sent to it. You cannot stop and start a service unless the security descriptor allows you to. The default security descriptor allows LocalSystem, Administrators, and Power Users to stop and start services. To change the security descriptor of a service, use SetServiceObjectSecurity.

The QueryServiceStatus or function returns a SERVICE_STATUS 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. 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 service control manager in each of the possible service states:

Service state	Stop	Other controls
STOPPED	(c)	(c)
STOP_PENDING	(b)	(b)
START_PENDING	(a)	(b)
RUNNING	(a)	(a)
CONTINUE_PENDING	(a)	(a)
PAUSE_PENDING	(a)	(a)
PAUSED	(a)	(a)

(a)	If the service accepts this control code, send the request to the service; otherwise, ControlService returns zero and GetLastError returns ERROR_INVALID_SERVICE_CONTROL.
(b)	The service is not in a state in which a control can be sent to it, so ControlService returns zero and GetLastError returns ERROR_SERVICE_CANNOT_ACCEPT_CTRL.
(c)	The service is not active, so ControlService returns zero and GetLastError returns ERROR_SERVICE_NOT_ACTIVE.

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