Re: [Cppcms-users] feedback after testing cppcms svn trunk compiled with msvc2005

[Artyom <art...@ya...>]

> AFAICT from  looking at libfcgi and mod_fastcgi code mod_fastcfg places
> the shutdown event  handle in the client's environment in the
> _FCGI_SHUTDOWN_EVENT_ variable. As  I've said I've taken the code from
> libfcgi\os_win32.c
> (www.fastcgi.com/dist/fcgi-2.4.1-SNAP-0910052249.tar.gz),  it works so
> it means that is can be shared between parent and child  processes.
> 

Ok, I'll take a look on this.

> >
> > The internal boost is not only subset of boost but  rather
> > renamed version of it (namespace boost -> namespace  cppcms_boost)
> >
> > These ifdefs should go in any case.
> 
> It's  good to know this. But boost is not a runtime dependency meaning
> that after  building cppcms if I use boost in the application linked
> with cppcms I don't  need to use the same version of boost, am I
> correct?
> 

Not correct.

For example you use in cppcms
 
 boost::foo() - from boost 1_36

This symbol is defined in cppcms.lib (assuming it is statically linked)

Now you are using boost_1_45 and you use boost::foo() as well and
new boost::foo() is not binary compatible with 1_36

Now linker may actually use the boost::foo from cppcms and not from the
header you compiled with (and this actually happens).

Now more then that if you use shared object under Unix it would 
happen with them as well. It is quite easy to show how programs
using different versions of boost::regex in same code base
crash.

So no you can't - even if the symbols are inline symbols and the library
is header only. Because compiler may create non-inlined weak symbols
and share them at link stage (and this really happens) in order to reduce
the size of the code.

Read this for more details: 

  
http://stackoverflow.com/questions/836875/creating-library-with-backward-compatible-abi-that-uses-boost


Regards,
  Artyom