Re: [Boost-users] tons of errors because boost::thread::thread() in thread/detail/thread.hpp is private

Subject: Re: [Boost-users] tons of errors because boost::thread::thread() in thread/detail/thread.hpp is private
From: Roman Perepelitsa (roman.perepelitsa_at_[hidden])
Date: 2009-11-08 05:14:52

2009/11/8 tiredashell <tiredashell_at_[hidden]>

> I am successfully using Boost.Thread on Windows without a hitch, but when
> porting my program to OSX I get the following compile error, followed by an
> enormous chain of errors that probably are a derivative of it:
>
> ./boost/thread/detail/thread.hpp:108: error:
> ‘boost::thread::thread(boost::thread&)’ is private
>
> When checking the class that it mentioned, it appears that it is in fact
> declared as private for some reason. Is there a reason I'm only receiving
> this error on OSX, and how can it be fixed?
>

Do you by any chance have code like this?
  void Foo() {}
  int main() {
    boost::thread t = Foo;
  }

Standard conforming compiler must reject this code, because boost::thread is
not copyable (even though all modern compilers know how to elide this copy).
As far as I remember, MS compiler will compile this code happily. The
solution is to change the last line to this:
  boost::thread t(Foo);

Here's another case where you might see the same problem:
  void Foo() {}
  void Bar(const boost::thread&) {}
  int main() {
    Bar(boost::thread(Foo));
  }

Again, MS compiler compiles it, but it should not, because C++03 requires
boost::thread to be copyable in this case.

HTH,
Roman Perepelitsa.