StartServiceCtrlDispatcher

StartServiceCtrlDispatcher

The StartServiceCtrlDispatcher function connects the main thread of a service process to the service control manager, which causes the thread to be the service control dispatcher thread for the calling process.

BOOL StartServiceCtrlDispatcher(
  const LPSERVICE_TABLE_ENTRY lpServiceTable
);

Parameters

lpServiceTable

[in] Pointer to an array of SERVICE_TABLE_ENTRY structures containing one entry for each service that can execute in the calling process. The members of the last entry in the table must have NULL values to designate the end of the table.

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.

The following error code 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.

Return code	Description
ERROR_FAILED_SERVICE_CONTROLLER_CONNECT	Typically, this error indicates that the program is being run as a console application rather than as a service. If the program will be run as a console application for debugging purposes, structure it such that service-specific code is not called when this error is returned.
ERROR_INVALID_DATA	The specified dispatch table contains entries that are not in the proper format.
ERROR_SERVICE_ALREADY_RUNNING	The process has already called StartServiceCtrlDispatcher. Each process can call StartServiceCtrlDispatcher only one time. Windows NT:  This value is not supported.

Remarks

When the service control manager starts a service process, it waits for the process to call the StartServiceCtrlDispatcher function. The main thread of a service process should make this call as soon as possible after it starts up. If StartServiceCtrlDispatcher succeeds, it connects the calling thread to the service control manager and does not return until all running services in the process have terminated. The service control manager uses this connection to send control and service start requests to the main thread of the service process. The main thread acts as a dispatcher by invoking the appropriate HandlerEx function to handle control requests, or by creating a new thread to execute the appropriate ServiceMain function when a new service is started.

The lpServiceTable parameter contains an entry for each service that can run in the calling process. Each entry specifies the ServiceMain function for that service. For SERVICE_WIN32_SHARE_PROCESS services, each entry must contain the name of a service. This name is the service name that was specified by the CreateService function when the service was installed. For SERVICE_WIN32_OWN_PROCESS services, the service name in the table entry is ignored.

If a service runs in its own process, the main thread of the service process should immediately call StartServiceCtrlDispatcher. All initialization tasks are done in the service's ServiceMain function when the service is started.

If multiple services share a process and some common process-wide initialization needs to be done before any ServiceMain function is called, the main thread can do the work before calling StartServiceCtrlDispatcher, as long as it takes less than 30 seconds. Otherwise, another thread must be created to do the process-wide initialization, while the main thread calls StartServiceCtrlDispatcher and becomes the service control dispatcher. Any service-specific initialization should still be done in the individual service main functions.

Example Code

For an example, see Writing a ServiceMain Function.

Requirements

Client	Requires Windows XP, Windows 2000 Professional, or Windows NT Workstation.
Server	Requires Windows Server 2003, Windows 2000 Server, or Windows NT Server.
Header	Declared in Winsvc.h; include Windows.h.
Library	Link to Advapi32.lib.
DLL	Requires Advapi32.dll.
Unicode	Implemented as StartServiceCtrlDispatcherW (Unicode) and StartServiceCtrlDispatcherA (ANSI).