please dont rip this site Prev Next

Handler info  Overview  Group

A Handler function is a function that a service program specifies as the control handler function of a particular Win32-based service. Handler is a placeholder for the application-defined name.


    DWORD fdwControl 

// requested control code



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




Requests the service to stop.


Requests the service to pause.


Requests the paused service to resume.


Requests the service to update immediately its current status information to the service control manager.


Requests the service to perform cleanup tasks, because the system is shutting down.

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



Range 128 to 255.

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

Return Values

This function does not return a value.


When a Win32-based service is started, its ServiceMain function should immediately call the RegisterServiceCtrlHandler function to specify a Handler function to process control requests.

The control dispatcher in the main thread of a Win32-based service process invokes the control handler function for the specified service whenever it receives a control request from the service control manager. After processing the control request, the control handler must call the SetServiceStatus function to report its current status to the service control manager.

The SERVICE_CONTROL_SHUTDOWN control should only be processed by services that must absolutely clean up during shutdown, because there is an extremely limited time (about 20 seconds) available for service shutdown. After this time expires, system shutdown proceeds regardless of whether service shutdown is complete. If the service needs to take more time to shut down, it should send out STOP_PENDING status messages, along with a waithint, so that the service controller knows how long to wait before reporting to the system that service shutdown is complete. For example, the eventlog service needs to clear a dirty bit in the files that it maintains, and the server service needs to shut down so that network connections arenít made when the system is in the shutdown state.

See Also

RegisterServiceCtrlHandler, ServiceMain, SetServiceStatus

See also:

file: /Techref/os/win/api/win32/func/src/f44_11.htm, 5KB, , updated: 2000/4/7 12:19, local time: 2022/5/20 10:32,

 ©2022 These pages are served without commercial sponsorship. (No popup ads, etc...).Bandwidth abuse increases hosting cost forcing sponsorship or shutdown. This server aggressively defends against automated copying for any reason including offline viewing, duplication, etc... Please respect this requirement and DO NOT RIP THIS SITE. Questions?
Please DO link to this page! Digg it! / MAKE!

<A HREF=""> Handler</A>

After you find an appropriate page, you are invited to your to this massmind site! (posts will be visible only to you before review) Just type a nice message (short messages are blocked as spam) in the box and press the Post button. (HTML welcomed, but not the <A tag: Instead, use the link box to link to another page. A tutorial is available Members can login to post directly, become page editors, and be credited for their posts.

Link? Put it here: 
if you want a response, please enter your email address: 
Attn spammers: All posts are reviewed before being made visible to anyone other than the poster.
Did you find what you needed?

  PICList 2022 contributors:
o List host: MIT, Site host, Top posters @20220520
* Page Editors: James Newton, David Cary, and YOU!
* Roman Black of Black Robotics donates from sales of Linistep stepper controller kits.
* Ashley Roll of Digital Nemesis donates from sales of RCL-1 RS232 to TTL converters.
* Monthly Subscribers: Gregg Rew. on-going support is MOST appreciated!
* Contributors: Richard Seriani, Sr.

Welcome to!