Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!apple!bionet!ames!lll-winken!uunet!mcvax!unido!pcsbst!horst
From: horst@pcsbst.UUCP (horst)
Newsgroups: comp.sys.apollo
Subject: Re: Implementation of Ada Tasks under Unix
Message-ID: <871@pcsbst.UUCP>
Date: 4 Jul 89 12:36:31 GMT
References: <88@runxtsa.runx.oz>
Reply-To: aida!horst@pcsbst.UUCP (horst kern)
Organization: PCS GmbH, Pfaelzer-Wald-Str. 36, 8000 Muenchen; West-Germany
Lines: 59

In article <88@runxtsa.runx.oz> jon@runx.oz (Jonathon Seymour) writes:
>How are Ada tasks implemented in the Apollo (Verdix) version running
>under 4.3bsd Unix?
>
>Specifically, is an Ada program ever blocked by the operating system
>even if one of its tasks is able to run?

Yes it does, at least in the Unix Sys V Version.
Try this one:

with text_io; use text_io;
procedure hk is
   task t;
   task body t is
      s : string (1..80);
      i : integer;
   begin
      put_line ("t");
      get_line (s,i);
      put_line (s (1..i));
   end;
begin
   put_line ("hk");
end;

I don't understand why it blocks. This one doesn't:

with text_io; use text_io;
procedure hk is
   task t;
   task body t is
      s : string (1..80);
      i : integer;
   begin
      put_line ("t");
      get_line (s,i);
      put_line (s (1..i));
   end;

   task tt;
   task body tt is
   begin
      put_line ("tt");
   end;
begin
   put_line ("hk");
end;

(Perhaps it's not an error but a feature.)

Regards,
 Horst

==========
Horst Kern                                     PCS Computer Systeme GmbH
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