RE: synApps usage on 64 bit systems

[Mark Rivers <rivers@cars.uchicago.edu>]

I have tested the scaler record on a 64-bit Windows system and it worked, but that is because in Visual Studio a "long" is 32-bits even on a 64-bit system.  Pointers are 64-bits, but longs are not.  You are probably the first to use it on a 64-bit Linux system.

I think that converting the scaler record to use a fixed 32-bit type is a good idea.  It might also be a good idea to define a new type locally which is set to epicsUInt32.  That way if EPICS ever supports a 64-bit integer DBR type for record fields only 1 line would need to be changed.  64-bit integers would be very useful for the scaler record, since there a currently a number of scalers with 64-bit counter depth.

Mark


-----Original Message-----
From: tech-talk-bounces@aps.anl.gov [mailto:tech-talk-bounces@aps.anl.gov] On Behalf Of Henrique Dante de Almeida
Sent: Tuesday, July 22, 2014 12:08 PM
To: tech-talk@aps.anl.gov
Subject: synApps usage on 64 bit systems

Hello, while using synApps with a test scaler IOC in a 64 bit linux machine I noticed some problems while reading and writing PV values. The problem was tracked down by another developer, some time ago, to be in synApps/support/std-*/src/scalerRecord.c, where the scalerRecord elements pr1, pr2, etc. are accessed using an unsigned long pointer (a type coercion to handle them as if they were a simple array). For example, in process():


static long process(pscal)
scalerRecord *pscal;
{
(...)
        unsigned long *ppreset = (unsigned long *)&(pscal->pr1);
(...)

Since pr1 and all other pr* are type epicsUInt32, using ppreset to access
the preset values is not supposed to work. Can anyone confirm this ?

The proposed patch was to replace the cast to unsigned long * to epicsUInt32 *,
or similar. Changing only process() and updateCounts() to use a 32 bit type was
enough to make the test scaler to work. I noticed that there are other variables
of type unsigned long, though. Would it make sense to write a patch to change all
the relevant variables to a fixed 32 bit type ?