Re: howto make system calls (newbie question)

["Samuel T. Harris" <u61783@gsde.hou.us.ray.com>]

Marin David Condic wrote:
> 
> Well, not everything in the world needs to be in an annex to the ARM. The
> Posix binding is a fair example. Of course, there you have the problem that
> the interface may not be made available by a given compiler and it might not
> be applicable in all environments anyway. That's a binding to a specific
> class of OS that may not be common across all OS's & one would want to give
> that some thought.

If I need POSIX, then that becomes a requirement for compiler choice.
POSIX compliance is also a common criteria for OS selection as well.

I also feel that POSIX is a good abstraction layer.

I believe most operating systems can be made to "fit" most
of the standard, at least when it comes to the most common
operations.

> 
> Is there a reason to maybe make an OS independent package available that
> provided some of the things that might exist in Posix, but might be provided
> by a different system in a different manner? Or is Posix widely spread
> enough that Ada could just say "If you want access to system facilities of
> this type - go see Posix"? Is the Posix binding going to just come with my
> compiler and I can go along fat, dumb and happy using it at will with no
> thought as to where to find it and no concern for transportability of my
> code? The answers are not clear to me.

POSIX come with Apex and VADS.

One can get Florist with GNAT, but I'm not sure of the
totality of support, especially when it comes to threads.

As to the most common operations, perhaps the approach
should be to define what is expected as the least common
denominator and standardize that in a POSIX way as what
every implementation is expected to support.

> 
> However, I still think there is room to add some standard libraries to Ada
> that make it more useful to the programmer. Clearly the Ada.Strings...
> branch is a good example - C may supply some fairly lame string handling
> functions but Ada83 provided none at all. Now Ada95 has an area of clear
> superiority in that you get some really good pre-fabricated string utilities
> that are just there on any implementation and are at your disposal. Might
> there not be similar libraries of things that Ada could provide in some
> standardized manner? If a C programmer can say "I can do this thing in C -
> how do I do it in Ada?" should it be fair game to ask how we might have that
> provided in all Ada implementations?

I'd like to see more work on numerics, especially matrix math.

> 
> I really wish the Ada Standard Library Working Group had managed to get
> somewhere with defining even a starting point for this sort of thing. Even
> if a library didn't come by virtue of the ARM, if it was available with a
> standard interface and provided by most, if not all, implementations, it
> would enhance the value of Ada to the programmer. Then we'd be off in other
> newsgroups asking "I can do this in Ada - how do I do it in your language?"

I do that whenever I can over at comp.software-eng and comp.object.

-- 
Samuel T. Harris, Principal Engineer
Raytheon, Aerospace Engineering Services
"If you can make it, We can fake it!"