Track FFI-allocated memory?

[timsneath]

Can this be used with FFI to track manually allocated memory (malloc / free)?

If so, it would be awesome to be able to use this to check for errors in FFI code... @dcharkes

[dcharkes]

Can this be used with FFI to track manually allocated memory (malloc / free)?

With NativeFinalizers

If you already use NativeFinalizers to invoke free: no.

Because then both the NativeFinalizer that frees the memory will run, and the Finalizer that tracks whether an object that holds on to memory cannot be canceled by the NativeFinalizer that invokes free.

Since the NativeFinalizer and leak_tracker both rely on the GC, you wouldn't get any new information anyway.

With Pointers

If you manually call free, but working directly withPointers: no.

The value and detach arguments do not count towards those objects being accessible to the program. Both must be objects supported as an Expando key. They may be the same object.

https://api.flutter.dev/flutter/dart-core/Finalizer/attach.html

Does not work on numbers, strings, booleans, records, null, dart:ffi pointers, dart:ffi structs, or dart:ffi unions.

https://api.flutter.dev/flutter/dart-core/Expando-class.html

With wrapper class without NativeFinalizers

If you call free manually, and you wrap your pointers in another class: yes.

The class that wraps pointer would have a free that cancels the Finalizer in the leak tracker.