Re: [boost] [spirit] Two failures caused by thread lib updated?

From: Anthony Williams (anthony_w.geo_at_[hidden])
Date: 2007-10-30 13:16:58

"Hartmut Kaiser" <hartmut.kaiser_at_[hidden]> writes:

> Peter Dimov wrote:
>
>> > the multi platform failures observed for grammar_mt_tests and 
>> > owi_mt_tests seem to correlate to the recent thread lib update:
>> >
>> > cxx: Error: ../boost/thread/pthread/thread.hpp, line 139: 
>> call of an 
>> > object
>> >           of a class type without appropriate operator() or 
>> conversion
>> >           functions to pointer-to-function type (badcallclsobj)
>> >           detected during instantiation of "void
>> >                     boost::thread::thread_data<F>::run() [with
>> >
>> > F=boost::reference_wrapper<single_grammar_object_task>]"
>> >                 f();
>> > ----------------^
>> >
>> > Anyone knows what's going on?
>> 
>> I think I do. The new Boost.Threads implements the proposed 
>> standard interface where F is expected to be a function 
>> object; std::reference_wrapper is, but 
>> boost::reference_wrapper isn't. The old Boost.Threads did not 
>> suffer from this problem since it stored F in a 
>> boost::function, which automatically recognizes 
>> reference_wrapper and "dereferences" it before the call.
>> 
>> This can be fixed on the user side by wrapping the 
>> reference_wrapper in a boost::bind, or it can be fixed on the 
>> Boost.Threads side. The third option, making 
>> boost::reference_wrapper callable, is a very risky change 
>> that I would advise against. 
>
> I strongly object against silently changing the Boost.Thread
> interface/semantics. So I'ld vote for 2)

I've checked in an update to Boost.Thread that handles
boost::reference_wrapper specially.

Anthony
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Anthony Williams
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