Menu
Does anybody know a "technique" to discover memory leaks caused by smart pointers? I am currently working on a large project written in C++ that heavily uses smart pointers with reference counting. Obviously we have some memory leaks caused by smart pointers, that are still referenced somewhere in the code, so that their memory does not get free'd. It's very hard to find the line of code with the "needless" reference, that causes the corresponding object not to be free'd (although it's not of use any longer).
I found some advice in the web, that proposed to collect call stacks of the increment/decrement operations of the reference counter. This gives me a good hint, which piece of code has caused the reference counter to get increased or decreased.
But what I need is some kind of algorithm that groups the corresponding "increase/decrease call stacks" together. After removing these pairs of call stacks, I hopefully have (at least) one "increase call stack" left over, that shows me the piece of code with the "needless" reference, that caused the corresponding object not to be freed. Now it will be no big deal to fix the leak!
But has anybody an idea for an "algorithm" that does the grouping?
Development takes place under Windows XP.
(I hope someone understood, what I tried to explain ...)
EDIt: I am talking about leaks caused by circular references.
708
Even when using smart pointers, is it still possible to have memory leak ? Yes, if you are not careful to avoid creating a cycle in your references.
One way to check for memory leak is to press and hold down your Windows key and tap the Pause/Break key to bring up System Properties. Click on the Performance tab and check System Resources for the percentage of free or available RAM.
The Memory Profiler is a component in the Android Profiler that helps you identify memory leaks and memory churn that can lead to stutter, freezes, and even app crashes. It shows a realtime graph of your app's memory use and lets you capture a heap dump, force garbage collections, and track memory allocations.
To find memory leaks and inefficient memory usage, you can use tools such as the debugger-integrated Memory Usage diagnostic tool or tools in the Performance Profiler such as the . NET Object Allocation tool and the post-mortem Memory Usage tool.
Note that one source of leaks with reference-counting smart pointers are pointers with circular dependancies. For example, A have a smart pointer to B, and B have a smart pointer to A. Neither A nor B will be destroyed. You will have to find, and then break the dependancies.
If possible, use boost smart pointers, and use shared_ptr for pointers which are supposed to be owners of the data, and weak_ptr for pointers not supposed to call delete.
112
The way I do it is simply: - on every AddRef() record call-stack, - matching Release() removes it. This way at the end of the program I'm left with AddRefs() without maching Releases. No need to match pairs,
37
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
