Re: menuFtype for 64 bit integers aka. long long and unsigned long long

[Andrew Johnson <anj@aps.anl.gov>]

Hi Hinko,

On 2012-03-15 Hinko Kocevar wrote:
> Are there any plans on adding support for 64-bit types to menuFtype (for
> 3.14.x branch)?

This will definitely never happen on the 3.14.x branch, and probably not on 
the 3.15.x branch either (there should be a 3.15.0 release out this summer).

> Are there any workarounds for this issue?

This idea is really horrible but it should work as long as you're very 
careful: If you are responsible for the device support and all the CA client 
programs and you can do any IOC-based processing that is necessary inside a 
subroutine or aSub record then you could pretend to the IOC code that your 64-
bit data types are epicsFloat64 (i.e. double) values and use casts to convert 
them back and forth.  However you won't be able to use any of the standard 
tools to look at the values, and I really don't recommend doing this.

> I guess this change would affect basic EPICS type handling code - not
> record, driver or device support code.

Adding new data types to EPICS is not easy, even just within the IOC, because 
there are function-tables and case statements all over the place.  If you also 
want to transmit that information over CA then there are even more 
complications.

The simplest way to handle 64-bit values is probably to split them into 2x32-
bit values that you pass around in arrays.

HTH,

- Andrew
-- 
Never interrupt your enemy when he is making a mistake.
-- Napoleon Bonaparte