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Using dfSplat to identify object leaks: Difference between revisions
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Using dfSplat to identify object leaks (view source)
Revision as of 16:06, 24 March 2020
, 24 March 2020→Our demo program
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=== Preface === | === Preface === | ||
One of the problems when developing a program which has a lot of dynamic objects is that you make sure that all the objects that | One of the problems when developing a program which has a lot of dynamic objects is, that you have to make sure that all the objects that have been created are also destroyed after usage. If you do not remove all of them after usage, then you end up with memory leaks. Memory leaks can be rather unpleasant as they cause problems which are hard to track down. | ||
A couple of areas where you see a lot of usage with dynamic objects is when working with XML and JSON. | A couple of areas where you see a lot of usage with dynamic objects is when working with XML and JSON. | ||
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</source> | </source> | ||
As you can see we are creating | As you can see we are creating 21 objects based on the cObject class and store the object ID's in Objects array. | ||
Then there's some code we are not showing where the objects are used for whatever and finally we destroy the objects. | Then there's some code we are not showing where the objects are used for whatever and finally we destroy the objects. | ||
But.. we only destroy objects with an even object ID, so we are leaking 10 objects on purpose | But.. we only destroy objects with an even object ID, so we are leaking 10 objects here, on purpose in order to display how this technique works. | ||
=== How to run the application in dfSplat === | === How to run the application in dfSplat === | ||
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[[File:dfSplat-LeakyObjects-Object-Inspector-Second-stop.png]] | [[File:dfSplat-LeakyObjects-Object-Inspector-Second-stop.png]] | ||
As you can see now, our | As you can see now, our 21 test objects have been created. | ||
So far, not all that exciting. | So far, not all that exciting. | ||
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=== Final notes === | === Final notes === | ||
* Beware that you use the Object Inspector and not the Panel Inspector as the latter one is not suitable for this task. The Object Inspector will enumerate ALL objects in your application and | * Beware that you use the Object Inspector and not the Panel Inspector as the latter one is not suitable for this task. The Object Inspector will enumerate ALL objects in your application and tests which of those objects actually exist or not. The Panel Inspector will only query the objects for the current panel and if objects are created dynamically, it won't actually show them! The Panel Inspector was created to give you much faster access to your current view or panel, but it does that at the cost of not enumerating every object (hence why it is faster) | ||
* If you want to test your code to see if it does correctly destroy all the dynamic objects it creates then it is most likely best to create a small temporary program for that. Obviously you can debug your full program, but the object inspector might be very slow to process every single object in your program on opening each time. | * If you want to test your code to see if it does correctly destroy all the dynamic objects it creates then it is most likely best to create a small temporary program for that. Obviously you can debug your full program, but the object inspector might be very slow to process every single object in your program on opening each time. | ||
