Experimental Physics and
Industrial Control System

Michael Davidsaver via Core-talk <core-talk at aps.anl.gov> · Tue, 4 Jan 2022 08:20:35 -0800

On 1/4/22 1:09 AM, Zimoch Dirk (PSI) via Core-talk wrote:
> The following breaktable name worked perfectly fine in EPICS 3.14:
> breaktable(ZX47-55LN+_142.8MHz) {
> 
> But in EPICS 7, registerRecordDeviceDriver.pl complains:
> Syntax error in 'breaktable(ZX47-55LN+_142.8MHz) {'
> 
> Not very informative, but let's try with quotes. Not the error is:
> Illegal breakpoint table name 'ZX47-55LN+_142.8MHz'
>         Identifiers are used in C code so must start with a letter, followed
>         by letters, digits and/or underscore characters only.
> 
> Why that? The name of a breaktable is never used as a C identifier. It is simply a string.
> 
> Such breaking changes are very inconvenient, as they require to change all the templates where the name is used and

Hi Dirk, I hope you can understand that this was almost certainly not
an intentionally breaking change!

It looks like a side effect of code re-use in the perl DBD parser code
because so many names in .dbd files do become C identifiers.

> make transition to EPICS 7 unnecessarily cumbersome.

I can't help but wonder if incremental testing with > 3.14 at some point
in the past decade, even only of compilation, would have helped PSI to
avoid this kind of frustration.

> Can we change it back?

I'll left this for Andrew.

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System