Re: Will Ada-95 Programs Written in MS Windows Run in MacOS and Linux Without Some Tweaking.

["Randy Brukardt" <randy@rrsoftware.com>]

"Austin Obyrne" <austin.obyrne@hotmail.com> wrote in message 
news:2b6dc37f-4aa6-4c18-be59-8c09f6f37f01@googlegroups.com...
On Tuesday, December 10, 2013 6:37:28 AM UTC, Randy Brukardt wrote:
...
>Please consider this procedure in the program that gave trouble,
>
>This is the defacto stripped down procedure
>
>EXIT when EOF;
>  EXIT when EOL;
>
>    FOR I IN 1 .. 3 LOOP
>      Ada.Integer_Text_IO.Get(File => InData, Item => W(I));
>      --Ada.Integer_Text_IO.Put(Item => W(I), Width => 8);
>    END LOOP;
>
>LOOP;
>LOOP;

I presume that there is a New_Line in there somewhere so that the line 
endings aren't lost completely.

But this isn't going to work, as Get for a character is defined as follows: 
"After skipping any line terminators and any page terminators, reads the 
next character from the specified input file and returns the value of this 
character in the out parameter Item."

So if you have any line endings in between the 1st and 2nd characters (or 
between the 2nd and 3rd characters), you'll end up ignoring them. I doubt 
that's what you want. (Ada abstracts the line, page, and file terminators so 
you don't have to worry about how they're represented. The problem being 
that you *can't* see how they're represented if you are using Text_IO.)

Using Text_IO without losing line endings and the like is tricky. I 
generally don't bother, just reading a line at a time with Get_Line and then 
process whatever I get. (And I just ignore page terminators, which are 
rarely used anyway.)

But if I was writing this sort of code, I wouldn't worry about line endings 
at all, and simply encrypt the file as binary data, using Stream_IO to read 
it in and out.

                                    Randy.