Re: JGNAT and Tasking problem

Re: JGNAT and Tasking problem

[Marc A. Criley]

"Marc A. Criley" wrote:
> 
> I've been working with JGNAT 1.1p lately on RedHat Linux 6.2 and having
> pretty good success.
> 
> However I'm now experiencing a problem with code that does tasking (up
> till now I've been working on single-threaded code, but now it's time to
> start getting concurrent).
> 
> Here's a simple example:
> 
> --------------------------------
> with Text_IO; use Text_IO;
> 
> procedure Simple_Task is
> 
>    task Simple is
>       entry Start;
>    end Simple;
> 
>    task body Simple is
>    begin
>       select
>          accept Start;
>       or
>          terminate;
>       end select;
>    end Simple;
> 
> begin
>    Put_Line("Start...");
>    Simple.Start;
>    Put_Line("Stop");
> end Simple_Task;
> --------------------------------
> 
> With GNAT 3.13p this compiles and runs just fine.
> 
> With JGNAT 1.1p it compiles, but when I try to run it I get the
> following JVM error:
> 
> Marc say: java simple_task
> Exception in thread "main" java.lang.IllegalMonitorStateException
>         at
> jgnat.adalib.system$task_primitives$operations.write_lock__2(s-taprop.adb:229)
>         at
> jgnat.adalib.system$task_primitives$operations.lock_all_tasks_list(s-taprop.adb:771)
>         at
> jgnat.adalib.system$task_primitives$operations.enter_task(s-taprop.adb:373)
>         at
> jgnat.adalib.system$task_primitives$operations.initialize(s-taprop.adb:834)
>         at jgnat.adalib.system$tasking._elabb(s-taskin.adb:186)
>         at ada_simple_task.adainit(b~simple_task.adb:84)
>         at simple_task.main(simple_task.adb)
> 
> I'm using the Blackdown distribution of Java for Linux; it's version
> information is:
> 
> Marc say: java -version
> java version "1.3.0"
> Java(TM) 2 Runtime Environment, Standard Edition (build
> Blackdown-1.3.0-FCS)
> Java HotSpot(TM) Client VM (build Blackdown-1.3.0-FCS, mixed mode)
> 
> I've looked over the JGNAT documentation and tasking is mentioned within
> it, so I wouldn't have expected any intrinsic problems using it.  Nor
> did I notice any sort of "init" preparation that had to be done before
> tasking could be used.
> 
> Any suggestions or advice would be appreciated!
> 
> Marc

Following up on my own message (for posterity's sake :-)...

The problem with tasking arose because I'd moved from JDK 1.2.2 to JDK
1.3, and the JGNAT 1.1p run-time library apparently has fits with that. 
When I reset the paths to use the 1.2.2 directory which I still had
installed, everything's worked fine since then.  (I'd hand-modified the
PATH in an xterm to test that, but apparently I messed something up and
was getting the same problem.)

So, JGNAT 1.1p seems to be fine with non-tasking Ada software under JDK
1.2.2 or JDK 1.3, but tasking works only with JDK 1.2.2.

Movin' on...

Marc