[Memory managament] long liveliness of application

[maximebd]

1. The C++ stack is pre-allocated and its size never changes. Whatever you allocate on the stack you will never see in the task manager or in a memory profiler that hooks on memory allocation functions.
2. Qt uses PIMPL a lot, so any QObject allocated on that stack will actually have most of its data allocated on the heap.
3. Variations of memory of +/- 100K is not a memory leak. They are often symptoms of an undisclosed implementation detail or OS memory management.
4. I wouldn't worry about memory fragmentation until your application gets to 2GB of memory usage.

Since the OP never claimed leaks of more than 100K over the lifetime of the application, I really wouldn't a memory leak there a all. Unless you have clear evidence that over a period of time, memory usage by the application has increased by at the very minimum 10MB (100MB would make it better), then I would just attribute that +/- 100KB to the task manager being not precise.

[d_stranz]

Thanks for the clarification about the stack. I had forgotten about the pre-allocation; I guess that's why you get stack overflow sometimes :-) Likewise with PIMPL; if a QDialog contains other QWidgets, all of those will certainly be heap-allocated even if the dialog object itself isn't.

And on Windows on my box at least (with 2GB RAM total), I can't get much over 1 GB of heap allocation before I run out of memory for a single app.

[amleto]

windows has single process memory limits as well