Re: xor

[Michael Moeller <mic2@t-online.de>]

On Wed, 28 Mar 2012, Georg Bauhaus wrote:

> On 28.03.12 14:18, Michael Moeller wrote:
>
>>  While this example compiles without complaints it
>> doesn't work with procedures declared in my package. How can I
>> make Sequential_IO visible there?
>
> Instantiate Sequential_IO where you need it:
> If the instance is needed in several packages,
> one solution is to create the instance at library level
> (for GNAT, read: in a file that only declares UB_IO).
> Then, add a with clause for this instance (UB_IO)
> everywhere you need visibility of UB_IO.
> (This is what context clauses are about; the other
> part of visibility is nesting.)
>
> -->8--
> with Package_Defining_UByte;
>
> package UB_IO is new Sequential_IO (Package_Defining_UByte.Ubyte);
> --8<--
>
>
> with UB_IO;
> package One is ...
>
> with UB_IO;
> package Two is ...
>
>
>
>> Its a little strange, though, how dead easy coding concurrency
>> on a Sun machine was recently while I'm not able to write out
>> some silly bytes using the very same language.
>
> This is not unusual, I think, insofar as virtually every language
> requires some effort when I/O is more than "print". Python,
> Java, Ada, C, C++, they all have some frowned upon simple I/O procedures,
> and then the real thing. The latter takes time getting used to.
>
> (A really good .NET programmer (C#) told me that, now that he
> needed to rewrite some software in Java (after a company takeover),
> he noticed that he didn't know the first things about formatting
> numbers in Java... Of course, he knew about formatting in general
> which made learning easier for him.)
>
Thanks again for your quick and competent answers. This works.

I agree with you on I/O. I've seen many languages and most often
I/O is pretty peculiar.

I don't want to push your helpfulness to far, but I still don't
know whether there is any means to determine the size of a file
from within Ada other than using a C subroutine calling fstat.

Regards,
Michael