use_error

use_error

[arcele]

USE_ERROR when using the Direct_IO Package, can anyone tell me what in the
heck this means, or where I can read up on it??? thanks....ryan =]

Re: use_error

[Fraser Wilson]

"arcele" <unhuh@hotmail.com> writes:

> USE_ERROR when using the Direct_IO Package, can anyone tell me what in the
> heck this means, or where I can read up on it??? thanks....ryan =]

Without code it's hard to say, but I expect you're doing something like

   use Direct_IO;

which you can't because it's a generic, and has to be instantiated.

Fraser.

Re: use_error

[arcele]

No, i'm not doing that, what i'm actually trying to do is set up a chain
with seperate overflow, my function that calls the error looks like this....

procedure addlink(inrec : in a_hote) is
  min_val : integer;
begin
  dir_io.open(notes, dir_io.inout_file, "notes.dat");
   min_val := inrec.next;
    while min_val /= 0 loop
      dir_io.read(notes, new_rec, dir_io.positive_count(min_val));
      min_val := new_rec.next;
    end loop;
  dir_io.write(notes, new_rec, dir_io.positive_count(min_val));
 end;


Fraser Wilson <blancolioni@blancolioni.org> wrote in message
news:fy71yr9sewb.fsf@blancolioni.org...
> "arcele" <unhuh@hotmail.com> writes:
>
> > USE_ERROR when using the Direct_IO Package, can anyone tell me what in
the
> > heck this means, or where I can read up on it??? thanks....ryan =]
>
> Without code it's hard to say, but I expect you're doing something like
>
>    use Direct_IO;
>
> which you can't because it's a generic, and has to be instantiated.
>
> Fraser.
>

Re: use_error

[Fraser Wilson]

"arcele" <unhuh@hotmail.com> writes:

> No, i'm not doing that, what i'm actually trying to do is set up a chain
> with seperate overflow, my function that calls the error looks like this....

OK, I'm an idiot.  Is the file read only?  See section A.13 in the Ada
reference manual (e.g. http://www.adapower.com/rm95/arm95_261.html#SEC261)
for the full story.

Fraser.

Re: use_error

[Mark D. McKinney]

arcele wrote:

> No, i'm not doing that, what i'm actually trying to do is set up a chain
> with seperate overflow, my function that calls the error looks like this....
> 
> procedure addlink(inrec : in a_hote) is
>   min_val : integer;
> begin
>   dir_io.open(notes, dir_io.inout_file, "notes.dat")

What does the LRM Say a use error is?? Is notes global ?? When do you 
close this file ?? Can addlink be called more than once ??
If you can aswer these qustions I think you can figure out at least on 
potential cause of your use_error.

> 
>    min_val := inrec.next;
>     while min_val /= 0 loop
>       dir_io.read(notes, new_rec, dir_io.positive_count(min_val));
>       min_val := new_rec.next;
>     end loop;
>   dir_io.write(notes, new_rec, dir_io.positive_count(min_val));
>  end;
> 
> 
> Fraser Wilson <blancolioni@blancolioni.org> wrote in message
> news:fy71yr9sewb.fsf@blancolioni.org...
> 
>> "arcele" <unhuh@hotmail.com> writes:
>> 
>>> USE_ERROR when using the Direct_IO Package, can anyone tell me what in
>> 
> the
> 
>>> heck this means, or where I can read up on it??? thanks....ryan =]
>> 
>> Without code it's hard to say, but I expect you're doing something like
>> 
>>    use Direct_IO;
>> 
>> which you can't because it's a generic, and has to be instantiated.
>> 
>> Fraser.
>> 

Re: use_error

[Wilhelm Spickermann]

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On 03-Apr-01 arcele wrote:
...
>     while min_val /= 0 loop
...
>     end loop;
>   dir_io.write(notes, new_rec, dir_io.positive_count(min_val));

You�re writing to position 0 here. 

Wilhelm

Re: use_error

[tmoran]

>USE_ERROR when using the Direct_IO Package, can anyone tell me what in the
>heck this means, or where I can read up on it??? thanks....ryan =]
  LRM A.13 "Exceptions in Input-Output", paragraph 10, says
"The exception Use_Error is propagated if an operation is attempted
that is not possible for reasons that depend on characteristics of
the external file. ...".  Are you trying to read from a printer, or
write to a read-only file, or something like that?

Re: use_error

[Michel Gauthier]

In article <9ado2r$vo1$1@slb1.atl.mindspring.net>,
  "arcele" <unhuh@hotmail.com> wrote:

> USE_ERROR when using the Direct_IO Package, can anyone tell me what in the
> heck this means, or where I can read up on it??? thanks....ryan =]

From my experience, Use_Error is an effect of an OS rejection.

Basic examples :
 - access rights violation
 - multiple opening of the same file
 - the OS file does not have a relevant structure