Re: ICE and TIPC

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

Jeff Hill wrote:
> In my example at the meeting I showed how DA could be enhanced to introspect
> the structure of the data - w/o an instance of the data. I communicated this
> information using an simple template class as follows.
>
> template < class T >
> struct TypedVoid 
> { 
> };
>
> I don't see any reason why the interface to this struct couldn't, or
> shouldn't, be extended as Ralph suggested at the meeting, to include member
> functions returning type codes for (B) above (it already does A).

Shouldn't a propertySurveyor also be given access rights information 
(i.e. whether a particular property is writable or not)?  Do you intend 
to use a different mechanism to communicate that somehow?  Unfortunately 
your very clever template mechanism only works with fully symmetrical 
property sets; in many cases I think we're going to have to write all 
three traverse() routines ourselves, to cope with read-only properties.

> WRT (2) above I have no problem using someone else's (Marty's) size locked
> type set in the CA protocol, but given the features in DA this would only be
> a organizationally cosmetic benefit, but not a feature required to make sure
> that the proper size locked type code for what the users is really using is
> discovered by CA for its use on the wire. Of course the TypedVoid interface
> (or whatever the correct class name is) should use a common type code set.

Can I urge that we make use of the size-locked integer types that are 
already defined for us in the C99 header files stdint.h and inttypes.h, 
rather than defining our own typedefs and having to check for each 
platform whether a long is 32 or 64 bits.  There are standard typdefs 
for int8_t, int16_t, int32_t, int64_t, uint8_t, uint16_t, uint32_t and 
uint64_t.  There are other typedefs defined too which might prove 
useful, but I won't go into them here.

C99 also defines a matching set of string macros for use in printf() and 
scanf() format specifications, which means you can pass an int64_t into 
printf() without worrying whether to say  "%ld"  or  "%lld"  in the 
format string - you use  "%" PRId64  instead.


- Andrew
--
Podiabombastic: The tendency to shoot oneself in the foot.