Experimental Physics and
Industrial Control System

"Ernest L. Williams Jr." <[email protected]> · Tue, 18 Oct 2005 17:35:55 -0400

On Tue, 2005-10-18 at 16:56 -0400, Kay-Uwe Kasemir wrote:
> On Oct 18, 2005, at 16:39 , Brian McAllister wrote:
> > I built and used EPICS base and many of the extensions on Alphas
> > (DECUnix/Tru64).  There were a few issues with older extensions  
> > that were
> > coded assuming pointer=int=long, mostly easily fixed.
> 
> The ChannelArchiver uses ftell(), feek() et al. which
> are usually defined with 'long' parameters.
> In addition, it actually assumes those 'long' values
> to be 32bit offsets.
> In case your 64bit compiler uses sizeof(long) != 4,
> it'll break.
> I assume it would be fairly easy to make it
> run on 64bit systems, but it would still
> have the same file size limits as on 32bit systems
> unless the file format is changed to also use 64bit
> pointers.
=========== The following is a porting tip form Apple ====
-- Files stored on disk

If you need your application to write binary data in a file format that
is shared between 64-bit and 32-bit versions, make sure that the size
and alignment of data structures are the same in both versions.
Specifically, this means that these programs should avoid storing data
of type long to disk.

Alternately, you can create a separate file format that is specific to
the 64-bit versions of their applications. Depending on the application,
this may be easier than maintaining a shared file format. For example,
Apple's 64-bit Mach-O format falls into this category.

Finally, never underestimate the convenience of a generic exchange
format such as XML.
========================================================================

Now, I think XML maybe out of the question unless some type of
compression is also used.  

> 
> -Kay
> 

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System