On Sun, Dec 9, 2012 at 5:00 AM, Vicente J. Botet Escriba <vicente.botet@wanadoo.fr> wrote:
Le 08/12/12 21:19, Beman Dawes a écrit :
On Sat, Dec 8, 2012 at 8:42 AM, Vicente J. Botet Escriba <vicente.botet@wanadoo.fr> wrote:
Hi,
any news on https://svn.boost.org/trac/boost/ticket/7278.
I could add them if you don't have the time now.
Go ahead!
As the change is a breaking change I would like to update all the libraries at once. I have identified the following dependent libraries: asio, filesystem, thread. Are there other libraries?
chrono? We need to contact Chris Kohlhoff to coordinate any asio changes with him. I have a vague recollection that he maintains the asio codebase elsewhere, so boost trunk is really just a mirror of some other repo. But I could be wrong about that.
Should I introduce the change conditionally so that the users could comeback to the preceding semantics?
I was thinking on defining a new BOOST_SYSTEM_NOEXCEPT that the users will use instead of BOOST_NOEXCEPT. The user could define BOOST_SYSTEM_NOEXCEPT as nothing to get the old semantic. Of course as the needed change in the user code is minor, we could also choose the drastic way and add a breaking change respect to the preceding version.
What happens if a user has built boost libraries without defining BOOST_SYSTEM_NOEXCEPT but then compiles his or her own code with BOOST_SYSTEM_NOEXCEPT defined, or visa versa? Isn't that an ODR violation? Could this result in the generated code for a call to a boost.system function being incompatible with the code that was generated when the library was built? And wouldn't such a bug be particularly insidious because it might not cause a problem until some future date when an error occurred? That seems a lot worse than the noisy compiler error that will happen if user code just broke. How many folks are using a compiler that supports C++11 noexcept, have C++11 turned on, and are deriving from boost::system_error? Or am I missing other cases where user code would break?
Beman up to you to decide.
I want to hear from others, particularly Chris, before making a decision. --Beman