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Related Hot Network Questions. Question feed. Stack Overflow works best with JavaScript enabled. Accept all cookies Customize settings. Console applications are good candidates for testing the core functionality of your Windows application without the unnecessary overhead of a GUI.
For a Windows based application, getting to know when such events occur is no problem since they are having a message queue assigned to them that is polled, and assuming that the concerned event is programmed for, it can be handled pretty easily. But this isn't the case with a console application that has no concept of a message queue. This article intends to discuss how you can handle all kinds of console-based events in any console application.
Once you have gone through it, you will see for yourself how trivial this seemingly helpless task is :. The first step in handling console application events is to setup an even trap, technically referred to as installing an event handler. The HandlerRoutine parameter is a pointer to a function that has the following prototype:. The parameter can take the following values:. Upon receiving the event, the HandlerRoutine can either choose to do some processing, or ignore the event.
If the routine chooses not to handle the event, it should return FALSE , and the system shall then proceed to the next installed handler. But incase the routine does handle the event, it should then return TRUE , after doing all the processing it requires. If the process doesn't respond within the timeout period, Windows shall then proceed to display the End Task dialog box to the user.
If the user proceeds to end the task, then the application will not have any opportunity to perform cleanup. Thus, any cleanup that is required should complete well within the timeout period.
Below is an exemplification of the handler routine:. Now that we have seen how the handler routine works, lets see how to install the handler. If either attempts are successful, the return value is TRUE. So, that's all there is to handling the console application events. After handler is installed, your application will receive the events as and by they come, and when the execution is about to be terminated, the handler maybe un-installed.
Pretty easy, eh :? This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below. Sign in Email. Forgot your password? Search within: Articles Quick Answers Messages. Tagged as VC6. View all page feedback. In this article. A signal that the system sends to all processes attached to a console when the user closes the console either by clicking Close on the console window's window menu, or by clicking the End Task button command from Task Manager.
A signal that the system sends to all console processes when a user is logging off. This signal does not indicate which user is logging off, so no assumptions can be made. Note that this signal is received only by services. Interactive applications are terminated at logoff, so they are not present when the system sends this signal. A signal that the system sends when the system is shutting down. Interactive applications are not present by the time the system sends this signal, therefore it can be received only be services in this situation.
Services also have their own notification mechanism for shutdown events. In most cases, after implementing HandlerRoutine , your console application will be able to detect an OS shutdown. For a GUI application, only shutdown and restart are considered suspending operations.
In some cases, we might need to detect sleep mode in order to message other system components that the PC is going to sleep.
GUI applications receive information about target events via window messages. Shutting a computer down and restarting it also cause a user session to end. Thus, messages about these events are delivered via the same window message. Note that we process shutdown and log-off events separately, since they are not necessarily connected.
In such cases, our application can behave in one of two ways:. The last option is possible for Windows Vista and later versions of Windows.
In this function, pay special attention to the dwLevel parameter. The mechanism of detecting necessary events for a Windows service is identical to the method for console applications, but with slightly different syntax and many more features. As with console applications, we need to create a callback function and register it as a service control requests handler.
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