Re: EPICS 7 incompatibility in errMdef.h

[Dirk Zimoch via Core-talk <core-talk@aps.anl.gov>]

On 02.04.19 16:24, Dirk Zimoch via Core-talk wrote:
> [I had originally sent this to tech-talk instead of core-talk by 
> accident. Sorry for the spam.]
>
> Hi folks,
>
> Today while compiling a driver for EPICS 7 I found an incompatibility.
>
> The function definition errSymbolAdd() (and others) have disappeared 
> from errMdef.h. Thus when compiling a driver including errMdef.h and 
> using errSymbolAdd(), I get a compiler warning because of the missing 
> function prototype.
>
> The prototypes are now in the new header file errSymTbl.h. But simply 
> including the new file instead is no good solution, because then the 
> driver does not compile with older EPICS versions any more.
>
> Instead I have use compiler branches based on EPICS versions. That is a 
> bit inconvenient.
>
> What is the policy about backward compatibility in EPICS 7? Should we 
> expect more compatibility breaking changes in the future in an attempt 
> to "move forwards" or will EPICS 7 aim to stay backward compatible for 
> 3rd party code like drivers?
>
> Dirk

The question is actually: Should I consider this a bug in EPICS 7 (and 
propose a fix)? Or was there a good reason for it and should I better 
put a preprocessor branch in the driver? (With the changes e.g. in rset 
and maybe in the future in dset as well such a branch may probably 
sooner or later be necessary anyway.)