Experimental Physics and
Industrial Control System

Andrew Johnson <[email protected]> · Thu, 28 Feb 2013 11:22:06 -0600

Hi,

On 2013-02-28 Michael Davidsaver wrote:
> On 02/28/2013 09:57 AM, Benjamin Franksen wrote:
> > (1) The script can be called more often than necessary:
> 
> I don't think this is the case as long as the command
> './create_some_files.pl' creates all three files (which I assume it what
> you intended).

If the target files can be created from more than one architecture and are 
generated in the O.Common directory or get installed into one of the common 
top-level directories (db, dbd, etc.) then you get this kind of problem, and 
it's actually very hard if not impossible to prevent a race between different 
target builds because they are not synchronized.

We get around that in Base now by always generating files into the O.<arch> 
directory and moving them into O.Common afterwards.  A move is an atomic 
operation in the file-system, so it doesn't matter if there is a race because 
the generated files *should* be identical.

We had to modify the installEpics.pl script so it now copies the file into the 
target directory using a temporary name and only then renames it to the final 
name.

- 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