Re: Importing a Unix function call

[Matthew Heaney <matthew_heaney@acm.org>]

"David Botton" <dbotton@hotmail.com> writes:

> Since in Ada non-scalar types are passed by reference (ie as pointers) to C
> functions you could get rid of the Access type and treat it just like C:

The file descriptor array is an out parameter.  The solution you propose
makes the array an in parameter.

I think this is another example of the fact that value-returning
subprograms (which we spell F-U-N-C-T-I-O-N in Ada) should be allowed to
have in out parameters.  

Clearly, what we want is the function

  function Pipe (Files : out File_Descriptor_Array) return Int;

but we can't express this thought using the language.