* Program_Error from library level task declaration...
@ 1996-07-27 0:00 Dale Stanbrough
1996-07-30 0:00 ` Theodore E. Dennison
0 siblings, 1 reply; 3+ messages in thread
From: Dale Stanbrough @ 1996-07-27 0:00 UTC (permalink / raw)
Hi,
I've tried to create a library level semaphore to be used
for screen locking. The semaphore is the standard implementation
using a task (yes, I know a protected object would be better).
The declaration is...
with semaphores; use semaphores;
package screen_lock is
screen:semaphore;
end screen_lock;
with screen_lock;
procedure main is
begin
null;
end;
However this causes a program_error. I'm at a bit of a loss as
to how to fix this. Does anyone have any bright ideas?
Dale
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: Program_Error from library level task declaration...
1996-07-27 0:00 Program_Error from library level task declaration Dale Stanbrough
@ 1996-07-30 0:00 ` Theodore E. Dennison
1996-07-31 0:00 ` Robert A Duff
0 siblings, 1 reply; 3+ messages in thread
From: Theodore E. Dennison @ 1996-07-30 0:00 UTC (permalink / raw)
Dale Stanbrough wrote:
> I've tried to create a library level semaphore to be used
> for screen locking. The semaphore is the standard implementation
> using a task (yes, I know a protected object would be better).
>
> The declaration is...
>
> with semaphores; use semaphores;
> package screen_lock is
>
> screen:semaphore;
>
> end screen_lock;
>
...
> However this causes a program_error. I'm at a bit of a loss as
> to how to fix this. Does anyone have any bright ideas?
It would help to see the code for "semaphores" as well. Typically,
I see program error when,
o Someone tries to rendezvous with a task that has terminated.
o The code depends on the order of package elaboration (and the
compiler guesses wrong).
o A function reaches the "end" without executing a "return"
statement.
(Note that if the "semaphore" task contains a terminate alternative,
the task may terminate once your main task terminates.)
--
T.E.D.
| Work - mailto:dennison@escmail.orl.mmc.com |
| Home - mailto:dennison@iag.net |
| URL - http://www.iag.net/~dennison |
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: Program_Error from library level task declaration...
1996-07-30 0:00 ` Theodore E. Dennison
@ 1996-07-31 0:00 ` Robert A Duff
0 siblings, 0 replies; 3+ messages in thread
From: Robert A Duff @ 1996-07-31 0:00 UTC (permalink / raw)
>Dale Stanbrough wrote:
>> I've tried to create a library level semaphore to be used
>> for screen locking. The semaphore is the standard implementation
>> using a task (yes, I know a protected object would be better).
>>
>> The declaration is...
>>
>> with semaphores; use semaphores;
>> package screen_lock is
>>
>> screen:semaphore;
>>
>> end screen_lock;
It looks like you're activating a task whose body is not yet elaborated
(see 3.11(12)). You should put pragma Preelaborate or Elaborate_Body on
the Semaphores package. If that's illegal (can't tell without seeing
it), put pragma Elaborate_All(Semaphores) on the Screen_Lock package.
- Bob
^ permalink raw reply [flat|nested] 3+ messages in thread
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1996-07-27 0:00 Program_Error from library level task declaration Dale Stanbrough
1996-07-30 0:00 ` Theodore E. Dennison
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