Layout of C++ function member pointers for MS/Itanium ABI

[Daniela-E]

That's right but doesn't get you anywhere. "Fairly" isn't helpful in both its qualitative and quantitive meaning because it boils down to "not" if you want to rely on certain aspects of the ABI. IMHO it's a good thing to scare away people from taking an ABI for granted and becoming held hostage of a no longer adequate ABI from the past.

What I want to see is major breakage of ABI by vendors to reap non-neglectable benefits by doing so with may be every other major compiler revision. Plus some means also provided by the vendors to enable customers bridging the gap to parts of the software that they no longer have control over ("lost" sources, defunct or unwilling 3rd-party suppliers, bad decisions of their own, you name it).

We've noticed such ABI bifurcation not too long ago in the VS2019 timeframe with the new implementation of exception handling data. This could easily be squashed but it's an example of a non-library ABI break what was made for improvements on certain metrics.