Experimental Physics and
Industrial Control System

Andrew Johnson <[email protected]> · Mon, 11 Mar 2013 16:34:18 -0600

Hi Michael,

On 2013-03-11 Michael Davidsaver wrote:
> epics-dev gets a new dependency on "perl (>= 5.10.0)".

As I said before, I don't think a libCap5.so built with Perl 5.10 is going to 
work if you try to load it into any other version of Perl (5.10.x might be Ok, 
but 5.12 or 5.14 will not).

> > Sounds like a good idea.  The Perl5 major version number matters for this
> > package, and it sounds like you might have to have more than one version
> > of that package available for install depending on which Perl5 version is
> > in use on the system — I would hope that dpkg can do something like that.
> 
> It would seem that this is not the case (I hadn't looked before). Only
> one version of perl can be installed. /usr/bin/perl is an executable
> provided by the package 'perl-base'. In contrast /usr/bin/python is a
> symlink to 'python2.7', an executable from the package 'python2.7-minimal'.

My point was that Ubuntu obviously has different Perl versions than Debian but 
Martin was still able to load your packages.  BTW Perl 5.10 is over 5 years 
old now, it was released in December 2007 (not that you could fix that, I do 
realize).

My Mac laptop has 3 versions of Perl installed, although only one of them came 
with the OS.  I built the others myself, and can switch between them with one 
command.  There was a problem aired here on tech-talk not too long ago that 
turned out to be because the site had a different version of Perl installed in 
/usr/local.  Some users had /usr/local/bin appear ahead of /usr/bin in their 
path but not others.

A regular EPICS installation can cope with multiple Perl versions, you just 
have to rebuild in the src/cap5 directory with PATH set to pick up each Perl 
version; copies of libCap5.so will then be installed into the appropriate 
directories and can coexist.

- Andrew
-- 
There is no such thing as a free lunch.  When invited for lunch,
it is best to check if you are there to eat, or to be eaten.
-- Clive Robinson

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System