Experimental Physics and
Industrial Control System

Michael Davidsaver via Tech-talk <tech-talk at aps.anl.gov> · Wed, 3 Apr 2024 10:37:09 -0700

On 3/31/24 13:53, William Kirstaedter via Tech-talk wrote:

Hello Core Devs,

I would like to know if you have already considered activating pvAccess for softIOCs by default.

Changing defaults seems certain to surprise someone.  I understand
the desire for change though as out of date defaults confuse new
users.

Historically, epics-base development has prioritized unsurprising
upgrades over unconfused newbies.  Still, changes are possible if
folks want to propose something concrete.  (aka. PRs welcomed)

I would probably adapt the Makefile template and simply copy the section from the example IOC:

# Link QSRV (pvAccess Server) if available
ifdef EPICS_QSRV_MAJOR_VERSION
     _APPNAME__LIBS += qsrv
     _APPNAME__LIBS += $(EPICS_BASE_PVA_CORE_LIBS)
     _APPNAME__DBD += PVAServerRegister.dbd
     _APPNAME__DBD += qsrv.dbd
endif

When PVXS is included in RELEASE, then PVXS_MAJOR_VERSION will be defined.
So some similar logic can be used.

ifdef PVXS_MAJOR_VERSION
_APPNAME__DBD += pvxsIoc.dbd
_APPNAME__LIBS += pvxsIoc pvxs
endif

Of course this raises the question of what to do if both are defined?

I have tried to design PVXS/QSRV2 so that both QSRV1 and QSRV2 can be linked
into the same executable.  In this happens, then on startup QSRV2 should
detect the presence of QSRV1 and disable itself.

That said, I would recommend avoiding this situation with Makefile logic like:

ifdef PVXS_MAJOR_VERSION # prefer QSRV2 :)
nasaAcq_DBD += pvxsIoc.dbd
nasaAcq_LIBS += pvxsIoc pvxs
else
ifdef EPICS_QSRV_MAJOR_VERSION # fallback to QSRV1
nasaAcq_LIBS += qsrv
nasaAcq_LIBS += $(EPICS_BASE_PVA_CORE_LIBS)
nasaAcq_DBD += PVAServerRegister.dbd
nasaAcq_DBD += qsrv.dbd
endif
endif

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System