trouble building libgcj on FreeBSD 2.2.7

Mon May 17 13:02:00 GMT 1999

>> >>>>> "Godmar" == Godmar Back <gback@cs.utah.edu> writes:
>> Godmar> I have found pthread_cancel to be a very bad match for java's
> Godmar> thread.stop().
>> I agree.
> Maybe we should just have Thread.stop() throw InternalError.
>> Or is it important for Thread.stop() to actually work?

Well...
That depends on your perspective and what you want to use Java for.
For libgcj without dynamic classloading, it's probably not strictly
necessary. 
Without a primitive such as atomic { } like in PERC it's probably
not very useful for such monolithic applications. You may want to read 
up on Nilsen's view on the subject [1] in a real-time context if you
haven't already.
I believe that being able to kill uncooperative processes is necessary
where java is used for untrusted code (applets, etc.), see [2].
However, Thread.stop probably isn't the way to do it.
Keep in mind that the main problem with stop() is that it comes
without a corresponding "pthread_cancel_disable/enable" which
means that you don't have an easy way to protect your shared 
data structures from corruption caused by asynchronous cancellation.
> I don't see how we could easily implement it on Linux, given that
> we're basically out of signals.
>
I think you'll have to share some signals with the linux-threads
implementation.
	- Godmar
[1]
@InProceedings{Nilsen+:plrtia98
 ,author = "Kelvin Nilsen and Simanta Mitra and Sairam Sankaranarayanan
 and Venkatesh Thanuvan"
 ,title = "Asynchronous {Java} Exception Handling in a Real-Time Context"
 ,year = 1998
 ,month = dec
 ,address = "Madrid, Spain"
 ,booktitle = "Proceedings of the IEEE Workshop on Prog. Lang.
 for Real-Time Industrial Applications"
}
[2]
@InProceedings{
 Back+:hotos7,
 author = "Godmar Back and Wilson C. Hsieh",
 title = "Drawing the red line in {Java}",
 booktitle = "Proceedings of the Seventh Workshop on Hot Topics in Oper
ating Systems", year = 1999,
 month = mar,
 address = "Rio Rico, Arizona",
 organization ="IEEE Computer Society",
}
( ftp://mancos.cs.utah.edu/papers/redline-hotos7-abs.html )