(j3.2006) (SC22WG5.3590) OPTIONAL arguments and C interop

[Robert Corbett]

Bill Long wrote:

> At the last WG5 meeting we cut off debate on a couple of issues related 
> to the C Interop TR due to time running out before convergence occurred.
> 
> One of the unresolved issues was the design for handling OPTIONAL 
> arguments in interfaces with BIND(C).  The current design, which has 
> been static for a couple of years, is that missing actual arguments 
> corresponding to dummies with the OPTIONAL attribute are represented as 
> actual arguments with the value NULL.   A side effect of this design is 
> that OPTIONAL and VALUE cannot be both specified for a particular dummy 
> argument.

Ths initial specification of the VALUE attribute did not allow the
combination of OPTIONAL and VALUE.  The extension to allow them
together was a late addition.  Adding that extension was daft.

Bob Corbett