What does 'last_event really return?

Hello everyone,

I would like to find out what the return type of the 'last_event
attribute really should be according to the LRM.  The reason I am
asking is because different tools behave differently on a piece
of code I am wrestling with.

I have a function in which one of the inputs is declared as a real.

    function MyFunction (X : real) return real is

When I call it I am trying to pass the time of an event into it
using the return value of 'last_event.

    SomeReal == MyFunction(SomeSignal'last_event);

Some of the tools I use take the above line, but others will generate
a type mismatch error and will only work if I do it with an explicit
type conversion.

    SomeReal == MyFunction(time'pos(SomeSignal'last_event)*1.0e-15);

The tool that works with the first example will also work with the
second, but I would like to find out which one is the PROPER syntax
according to the language reference manual.  I read something about
the two different representations of time in the analog and digital
solvers, but I don't understand it completely.  Could someone please
explain this to me?

Thanks,

Arpad Muranyi
Intel Corporation
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