Re: [boost] [thread] [repost] Why the at_thread_exit cleanup function is const?

Subject: Re: [boost] [thread] [repost] Why the at_thread_exit cleanup function is const?
From: Anthony Williams (anthony.ajw_at_[hidden])
Date: 2009-01-24 06:13:00

"vicente.botet" <vicente.botet_at_[hidden]> writes:

> Hello, I first posted this two months ago, allow me to repost just in
> case it went unnoticed:

Sorry for the lack of response.

> From: "vicente.botet" <vicente.botet_at_[hidden]>
>
> If I remove the const on operator()() 
>     struct mycallable1
>     {
>         void operator()()  {
>             std::cout << "mycallable1" << std::endl;
>         };
>     };
>
>     void my_thread() {
>         std::cout << "my_thread" << std::endl;
>         mycallable1 x;
>         boost::this_thread::at_thread_exit(x);
>     }
>
> I get the following error:
>
> gcc.compile.c++
> ..\..\..\bin.v2\libs\interthreads\test\hello_world.test\gcc-4.3.2\debug\target-os-cygwin\threadapi-pthread\threading-multi\hello_world.o
> ../../../boost/thread/detail/thread.hpp: In member function `void
> boost::detail::thread_exit_function<F>::operator()() const [with F =
> mycallable1]': ..\example\hello_world.cpp:52: instantiated from here
> ../../../boost/thread/detail/thread.hpp:474: error: passing `const
> mycallable1' as `this' argument of `void mycallable1::operator()()'
> discards qualifiers
>
>
> Why the cleanup function must be const?

I can't think of a good reason just now.

Anthony
-- 
Anthony Williams
Author of C++ Concurrency in Action | http://www.manning.com/williams
just::thread C++0x thread library   | http://www.stdthread.co.uk
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