Re: [boost] Re: future of boost.threads

From: Slawomir Lisznianski (slisznianski_at_[hidden])
Date: 2004-02-08 15:01:42

Jeff Garland wrote:
> On Sun, 08 Feb 2004 11:23:37 -0500, David Abrahams wrote
> 
>>Christopher Currie <christopher_at_[hidden]> writes:
>>
>>
>>>Slawomir Lisznianski wrote:
>>>
>>>>Are there any plans to support handling of exceptions thrown during
>>>>joinable thread execution? I recall Usenet discussions with proposals
>>>>varying from Futures to throwable join():
>>>>try {
>>>>  thread.join();
>>>>}
>>>>catch (std::runtime_error& e) {
>>>>  ...
>>>>}
>>>>Any ideas?
>>>
>>>Doesn't this require a certain amount of compiler support? 
>>
>>Yes.
> 
> 
> Why? Corba throws user exceptions across remote procedure calls without
> changes to the c++ compiler (of course there is an IDL compiler).  Also, Rogue
> Wave has a portable library that does this for threading.  

I think I agree with Jeff. Although without compiler support library 
code cannot propagate arbitrary exceptions across threads, we could 
manage to propagate exceptions declared ahead of time, possibly when 
thread object is created. Something along the lines of:

boost::thread<runtime_error, ...> my_thread(functor);

...and later:

try {
  my_thread.join()
}
catch (runtime_error&) {
}
catch (<any exception declared in type list above>&) {
}

I'm more uncertain how to approach the problem of (multiple) exceptions 
thrown in threads that are part of the single group.

>>>IIRC, some compilers don't support throwing exceptions across thread
>>>boundaries...
>>

I wouldn't expect compilers to do so. The needed support would have to 
come entirely from the library.

Slawomir Lisznianski; [ www.rhapsodia.org ]