Experimental Physics and
Industrial Control System

Background:

Between RHEL6 and RHEL7, the indirect linking policy changed.

Before, applications could rely on symbols from indirectly linked libraries to be available. E.g., an EPICS IOC could just use pthread calls without explicitly linking against it, knowing that EPICS Base libraries had been linked against pthread and would make the shared library available at run time.

Now, each application must explicitly link against all libraries it uses. (Careful with libraries that use C++ templates in their APIs. They inject source code into your application, so that it may e.g. call pthread without you knowing it. Under the new policy, the pthread library needs to be added in such a case.)

See also: https://fedoraproject.org/wiki/UnderstandingDSOLinkChange

Cheers,
~Ralph

Hi John,

 

I found and fixed the problem.  The pthread and rt libraries needed to be added to PROD_SYS_LIBS.  They appear to be added automatically by the EPICS build system for static builds, but not for dynamic builds.

 

The master branch should now work correctly for dynamic builds.

 

Mark