Re: [Boost-users] Annoying compiler warnings in asio/error.hpp

Subject: Re: [Boost-users] Annoying compiler warnings in asio/error.hpp
From: Hite, Christopher (Christopher.Hite_at_[hidden])
Date: 2010-07-16 10:08:16

> What you describe here is the opposite of what is stated in the lib. 
> As far as I understand the author's intention by declaring a global
variable 
> static: introdcution of an own copy of this var in each compilation
unit.  

The author just wanted a constant which you ask for a name/message.

Actually the variable ssl_category is not used anywhere.  They call
get_ssl_category() which has a static function variable.  

That is another good trick to create a global variable which exists in
all compilation scopes.  Code like this in a header will generate on
instance of X shared between compilation scopes.

Class X{}

inline X& getOneAndOnlyX(){
        static X x;
        return x;
}

Anyways I'm guessing you could just kick ssl_category.  I can't find
these constants documented anywhere in the reference.  ssl_category
isn't used in tests.  Some of the others are used, but since they are
the same as what the inline functions would return.

Perhaps the author was afraid in a multi threaded environment functions
like getOneAndOnlyX() aren't safe.  I know gcc by default generates
atomic ops so only one X is constructed.  Perhaps the idea was to ensure
all these things were created before main() gets a chance to start
threads.

I don't have a checkout.  Maybe someone could svn blame the file and
find out who defined these things and ask them what they were thinking.

Chris