Re: EPICS base-3.15.9 fails to build with GCC-15

[Michael Davidsaver via Tech-talk <tech-talk at aps.anl.gov>]

On 9/22/26 1:38 AM, Dmitry Yu. Bolkhovityanov via Tech-talk wrote:

Hi!

GCC-14 becomes mainstream (e.g. Debian-13), and familiar base-3.15.6 fails to build with it.  Fotrunately, 3.15.9 was built successfully, but I wanted to check it for "future-proofness" and tried building with GCC-15 and GCC-16.  It had failed with both.
...

GCC 14+ have been aggressive in trying to discourage use of error-prone language constructs, and the older standards which permitted them.  Some of the compile errors you mention should be avoidable by building with "make CMD_CFLAGS=-std=c89" (or C11 as Remi mentions).  I think not a long term solution, but with this older code maybe long enough?

The 3.15.9 is currently the latest release of EPICS3, which is still widely used.  And there are chances it will become unbuildable on modern systems in a year or two. 

This has already happened to the 3.14 branch, and the 3.13 branch before that, and the 3.12 branch...  The pattern is clear.  Code which is not being maintained will become unbuildable in newer environments.  To my mind, those with an interest in running older code on newer systems need to step up and help with this work.

Maybe the time for base-3.15.10 had come? 

As I write this, the most recent commit on the 3.15 branch dates from Dec. 2025.  About 10 months ago.  At this point, the prerequisite for any work will be to update the CI build configuration (Github Actions and Appveyor).  Mostly this will mean applying changes equivalent to those made to the 7.0 branch.  Then finding and "git-cherry-pick"ing the fixes which have been made to the 7.0 branch.  All of which I think makes this an ideal task for a new contributor (hint again).