Re: libgcj/78

[green at cygnus dot com]

The following reply was made to PR libgcj/78; it has been noted by GNATS.

From: green@cygnus.com
To: green@cygnus.com, java-gnats@sourceware.cygnus.com, tromey@cygnus.com
Cc:  
Subject: Re: libgcj/78
Date: 2 Nov 1999 18:56:55 -0000

 Synopsis: pthread thread cancellation problem
 
 State-Changed-From-To: open->analyzed
 State-Changed-By: green
 State-Changed-When: Tue Nov  2 10:56:55 1999
 State-Changed-Why:
     Now I'm thinking we should remove Thread.stop and friends.
     JDK 1.1 stongly recommends not using them, and they're
     deprecated in JDK 1.2.  After speaking with Ulrich Drepper,
     I think it's almost impossible to support them safely with
     the existing glibc and gcc technology.  Eventually the plan
     is to add structured EH to gcc, and then use EH in glibc.
     Until then, we should really avoid throwing, or longjmp'ing
     out of callbacks.  The current implementation is broken in
     an even more subtle way.  Cancelling the thread will invoke
     various registered callbacks.  One of the callbacks does
     the throw (or longjmp).  Another registered callback is
     from the GC, where it deregisters interest in the thread.
     However, the cancelled thread can catch the exception and
     continue running!   Maybe we should just remove this
     functionality before it causes more problems for people.
 
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