StartService function

Starts a service.


BOOL WINAPI StartService(
  _In_     SC_HANDLE hService,
  _In_     DWORD     dwNumServiceArgs,
  _In_opt_ LPCTSTR   *lpServiceArgVectors


hService [in]

A handle to the service. This handle is returned by the OpenService or CreateService function, and it must have the SERVICE_START access right. For more information, see Service Security and Access Rights.

dwNumServiceArgs [in]

The number of strings in the lpServiceArgVectors array. If lpServiceArgVectors is NULL, this parameter can be zero.

lpServiceArgVectors [in, optional]

The null-terminated strings to be passed to the ServiceMain function for the service as arguments. If there are no arguments, this parameter can be NULL. Otherwise, the first argument (lpServiceArgVectors[0]) is the name of the service, followed by any additional arguments (lpServiceArgVectors[1] through lpServiceArgVectors[dwNumServiceArgs-1]).

Driver services do not receive these arguments.

Return value

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. Others can be set by the registry functions that are called by the service control manager.

Return codeDescription

The handle does not have the SERVICE_START access right.


The handle is invalid.


The service binary file could not be found.


An instance of the service is already running.


The database is locked.


The service depends on a service that does not exist or has been marked for deletion.


The service depends on another service that has failed to start.


The service has been disabled.


The service did not start due to a logon failure. This error occurs if the service is configured to run under an account that does not have the "Log on as a service" right.


The service has been marked for deletion.


A thread could not be created for the service.


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.



When a driver service is started, the StartService function does not return until the device driver has finished initializing.

When a service is started, the Service Control Manager (SCM) spawns the service process, if necessary. If the specified service shares a process with other services, the required process may already exist. The StartService function does not wait for the first status update from the new service, because it can take a while. Instead, it returns when the SCM receives notification from the service control dispatcher that the ServiceMain thread for this service was created successfully.

The SCM sets the following default status values before returning from StartService:

  • Current state of the service is set to SERVICE_START_PENDING.
  • Controls accepted is set to none (zero).
  • The CheckPoint value is set to zero.
  • The WaitHint time is set to 2 seconds.

The calling process can determine if the new service has finished its initialization by calling the QueryServiceStatus function periodically to query the service's status.

A service cannot call StartService during initialization. The reason is that the SCM locks the service control database during initialization, so a call to StartService will block. After the service reports to the SCM that it has successfully started, it can call StartService.

As with ControlService, StartService 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, StartService fails with ERROR_SERVICE_REQUEST_TIMEOUT. This is because the SCM processes only one service control notification at a time.


For an example, see Starting a Service.


Minimum supported client

Windows XP [desktop apps only]

Minimum supported server

Windows Server 2003 [desktop apps only]


Winsvc.h (include Windows.h)





Unicode and ANSI names

StartServiceW (Unicode) and StartServiceA (ANSI)

See also

Service Functions
Service Startup