> From: Tyler Retzlaff [mailto:roret...@linux.microsoft.com] > Sent: Tuesday, 13 February 2024 07.46 > > The zero sized RTE_MARKER<n> typedefs are a GCC extension unsupported > by > MSVC. Replace the use of the RTE_MARKER typedefs with anonymous > unions. > > Note: > > v1 of the series tried to maintain the API after some study it has been > discovered that some existing uses of the markers do not produce > compilation > failure but evaluate to unintended values in the absence of adaptation. > For this reason the existing markers cannot be removed because it is > too hard > to identify what needs to be changed by consumers. While the ABI has > been > maintained the subtle API change is just too risky. > > The question I'm asking now is how to gracefully deprecate the markers > while allowing consumption of the struct on Windows. > > I propose the following: > > * Introduce the unions as per-this series except instead of adding > members > that match the original RTE_MARKER field names provide *new* names. > * Retain (conditionally compiled away on Windows) the existing > RTE_MARKER > fields with their original names. > * Convert in-tree code to use the new names in the unions. > > The old names & markers would be announced for deprecation and > eventually > removed and when they are the conditional compilation would also go > away. > > Thoughts?
Seems like the right thing to do! The modified type of rearm_data might not be noticed by out-of-tree PMD developers, so using a new name for the new type reduces the risk. If some of the markers maintain their type or get a compatible type (from an API perspective), they can keep their names.
