Re: [boost] [any] new version

Subject: Re: [boost] [any] new version
From: Roman Perepelitsa (roman.perepelitsa_at_[hidden])
Date: 2011-09-01 02:33:24

2011/9/1 Julien Nitard <julien.nitard_at_[hidden]>

> >
> > >
> > > It can't, you will end up with a different function static variable for
> > > each translation unit.
> >
> > This isn't the case. If you have an inline function with a static
> variable
> > in it, it'll be the same variable in all translation units.
> >
> > *7.1.2p4 A static local variable in an extern inline function always
> refers
> > to the same object.*
> >
>
> ... which I guess means you can still end up with several definitions when
> using dynamic libraries ?

If they don't export the function properly, then yes. By messing with the
set of exported symbols in shared libraries one can end up with all sorts of
anomalies:  failure to dynamic_cast std::string to std::string, or failure
to catch exceptions even when the type of the exception thrown is the same
as the type of the exception in the catch clause.

If I wanted to guarantee that there is exactly one instance of the variable
regardless of the symbol export map, I'd put the variable in a shared
library.

Roman Perepelitsa.