Stream class virtual destructor

[gicking]

Hi there,

first of all thanks a lot for your great work and effort! (thumbsup)

I just stumbed accross an issue with the Stream class, when writing a destructor for a derived class. Specifically, the class has a variable pSerial of type Stream*, which is allocated via

this->pSerial = (SoftwareSerial*) (new SoftwareSerial(this->pinRx, this->pinTx, this->inverseLogic));

But when I try to delete it inside the class constructor via

delete (SoftwareSerial*) this->pSerial; or delete static_cast<SoftwareSerial*>(this->pSerial);

I get the warning
warning: deleting object of polymorphic class type 'SoftwareSerial' which has non-virtual destructor might cause undefined behavior [-Wdelete-non-virtual-dtor]

If I understand it correctly, the issue is that class Stream does not have a virtual destructor - or any destructor for that matter, see here.

I understand that using SoftwareSerial dynamically is uncommon, but I have no control over the "correct" use of my library. Therefore I want to avoid memory leaks by releasing the instance again.

To avoid this issue I propose to add a dummy virtual destructor to class Stream. Alternatively, do you know how I could avoid this issue? I tried calling the destructor explicitly

((SoftwareSerial*) this->pSerial)->~SoftwareSerial();

which does compile without warning. However, Co-Pilot advises against it, as it doesn't seem to release allocated memory. Any other ideas?

[matthijskooijman]

See also arduino/ArduinoCore-API#218 for a similar discussion.

[gicking]

closed due to parallel discussion arduino/ArduinoCore-API#218