Experimental Physics and
Industrial Control System

Andrew Johnson <[email protected]> · Wed, 8 Dec 2010 15:37:55 -0600

Hi Lewis,

On Wednesday 08 December 2010 14:20:38 J. Lewis Muir wrote:
> On 12/8/10 2:06 PM, Andrew Johnson wrote:
> > Michael suggested replacing our build system with CMake, but he did find
> > some issues with doing so and I don't think that's up to the job, and it
> > was not popular in my recent survey (aside from the effort needed to
> > train and support all of the EPICS developers out there in any new
> > system).
>
> I'd be curious to know what the issues were and why you don't think it's
> up to the job.

Ok, maybe instead of "it's not up to the job" I should have said "the result 
would not be as easy for developers to configure as the current build system".  
Michael is the best person to say what the issues were, but I'm pretty sure 
that he only had it working on Linux and RTEMS.  I don't know whether CMake 
runs on all our host architectures, but I'm guessing that supporting the 
Microsoft compiler on Windows might take some work; one criterion that I will 
insist on is that we not drop any major targets.

You can find Michael's latest version on Launchpad, browse it here:
  http://bazaar.launchpad.net/~mdavidsaver/epics-base/cmake/files

One example about the complexity issue, the CMakeLists.txt files in his src/* 
directories do seem to be longer than their companion Makefiles.  I remember 
Michael commenting about problems defining macros (routines, ?) for CMake in a 
central place, he had to copy some things into every place that needed them 
(don't know if that's been fixed since).  I'm not sure if he looked at 
building support modules, he doesn't seem to build the src/makeBaseApp 
directory at all.

> I'm also hoping you're careful about how much weight you give the survey
> results.  When I pointed out some of the weaknesses in the survey, you
> agreed and noted the results wouldn't be treated too seriously.  But now
> you seem to be using the survey results as a reason for not switching to
> CMake.

I'm using the survey as an indication of how much work it might be to persuade 
the community to switch.  I haven't said anything like "over my dead body," 
but there are many things that would need to be solved before we could do so.  
The community's reaction to that question tells me that they are probably not 
frustrated by the existing build system, or if they are it's not enough to 
make them eager to find an alternative.

- Andrew
-- 
If a man is offered a fact which goes against his instincts, he will
scrutinize it closely, and unless the evidence is overwhelming, he will
refuse to believe it.  If, on the other hand, he is offered something
which affords a reason for acting in accordance to his instincts, he
will accept it even on the slightest evidence.  -- Bertrand Russell

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System