[Discussion] RemoveVariables confusion

[NAThompson]

The documentation for IO::RemoveVariable states:

Remove functions must be used with caution as they generate dangling Variable/Attributes pointers or references if they didn’t go out of scope.

I am confused by this; does the IO not have ownership of the data? If it does not own it, then shouldn't calling RemoveVariable be prohibited?

[NAThompson]

From a conversation with Norbert:

staging read engines use this to clean out the IO group and fill it with new variables for the next step (InsituMPI).

[williamfgc]

adios2::Variable<double> var = io.DefineVariable<double>("to-be-dangled", ... );
io.RemoveVariable("to-be-dangled"); // io has ownership, so it can remove it
/// var is undefined (not even false) is dangling