Re: [Boost-users] mixing c++98 with c++11

Subject: Re: [Boost-users] mixing c++98 with c++11
From: Michael Chisholm (chisholm_at_[hidden])
Date: 2013-12-09 15:40:34

On 12/6/2013 6:19 PM, Chris Stankevitz wrote:
> On Fri, Dec 6, 2013 at 3:11 PM, Michael Chisholm <chisholm_at_[hidden]> wrote:
>> The headers are supposed to tell you what symbols are exported from the
>> binary (among other things).  If you change the headers without changing the
>> binary, those won't match up, and I think you're liable to have link errors.
>
>
> Andy,
>
> Thank you for your reply.  Is this a correct interpretation of what
> you are saying:
>
> I use Ubuntu Linux's apt-get to install boost.  I need to ask Ubuntu
> which flavor of GCC was used to compile boost (c++98 or c++11).  Then,
> when I build my applications using GCC I must use the same flavor.
>
> For example, if Ubuntu compiled boost with c++98, I cannot write a
> c++11 application that uses system-provided boost libraries.
>
> Thank you again,
>
> Chris

That is correct.  Of course in any particular case, it depends on the 
headers in use.  E.g. if enabling c++11 mode enables declaration of a 
move constructor in a header, but the definition doesn't exist in the 
library, you'll get a link error.  If nothing changes when you enable 
c++11 mode, it probably won't matter.  But in general, I wouldn't trust 
it to work.  Consider also there are tools like pkg-config that let the 
compile/link settings of a dependency be discovered automatically.  I 
think there's a similar mechanism for cmake-built libraries too.  I 
would say that's further evidence that the compile/link settings of your 
dependencies are important to know, when using them in your app.

Btw, there is a C++03 standard in between '98 and '11.  I suspect '03 is 
in widest use right now.

Also, I'm no linux guru, but I think you can get source packages 
corresponding to the binary packages, if you want to see exactly how the 
binaries are built.  E.g. maybe with 'apt-get source ...'?

Andy