On 6/11/21 6:00 AM, 'pvr...@btinternet.com' via fltk.general wrote:

My application has a view based on Fl_Tree which displays a report of the database in the app. Everytime I regenerate the report with different parameters (or a different database) it looks like the the Fl_Tree_Item created by Fl_Tree::add() are not deleted by the Fl_Tree::clear().

I was getting humungous memory leakage problems resulting in my app building up to several hundreds of MB quite quickly and I think eventually causing the app to crash. I was getting spurious crashes that I couldn't resolve. I have resolved the two largest issues, so the Fl_Tree issue is the last remaining one. Every time I regenerate the report memory usage increased by about 1 MB, so it's
not too great an issue, just would like to fix it.

Is it a simple matter starting at the root item and working my way through the tree and deleting all the branches?

I am using fltk-1.4.0 using a snapshot taken April 2020.

    To test, I backgrounded "test/tree", then ran the following to keep an eye on the app's
    memory use:

        while [[ 1 ]]; do sleep 3; ps u --pid <<PID_OF_TREE>>; done

    then in the test/tree app, repeated these two tests while watching the VSZ/RSS values
    of the above command:

        Test just the default tree with 500 items

            1) Hit the button: Test Operations -> "Clear All"
            2) Hit the button: Test Operations -> "Rebuild Tree"
            3) Goto 1

        Test creating/removing the 500 + 20,000 items

            1) Click the "ROOT" item (to highlight it)
            2) Hit the button: Test Operations -> "Add 20,000" (creates an additional 20k items at bottom of tree)
            3) Hit the button: Test Operations -> "Clear All"
            4) Hit the button: Test Operations -> "Rebuild Tree"
            5) Goto 1

    When running the second test, you have to wait for memory to stabilize after the
    first iteration.

    What should happen is the numbers for VSZ/RSS reach a certain value, and then don't
    keep getting bigger on each iteration. If they did get bigger each iteration, that'd be a leak.

    The numbers will NOT get smaller when you hit the "Clear All" button, but should not grow
    each iteration.