[kde-freebsd] devel/smokekde

[Dimitry Andric]

On Aug 13, 2013, at 07:48, Schaich Alonso <alonsoschaich at fastmail.fm> wrote:
> devel/smokekde seems to use the -fno-exceptions compiler switch to disable
> C++ exceptions, while at the same time it refers to some inline code of
> akonadi that uses exceptions
> (${KDEPREFIX}/include/akonadi/itempayloadinternals_p.h:164 for example),
> which therefore fails to build. The way I see it we can either remove the
> -fno-exception flag and eventually have an exception be thrown into non-C++
> code (undefined behaviour), or remove akonadi wrapper generation from
> smokekde, which eventually will become troublesome if some smokekde consumer
> (other ports or other parts of smokekde as well) attempts to use it.

This is most likely the same problem I discussed with rakuco on IRC,
e.g. clang generates errors when parsing the template, instead of when
instantiating it, as gcc does.

Take for example:

  template<typename T> void foo() { throw 42; }

then g++ -fno-exceptions will not complain, but if you add:

  void bar() { foo<int>(); }

g++ -fno-exceptions will give a similar error ("exception handling
disabled, use -fexceptions to enable").

A workaround for clang is to use the -fdelayed-template-parsing option,
which will postpone (most of) the parsing until instantiation time.

Of course the best option is for the upstream software to fix their
inline code to only use exceptions when they are enabled, for example by
testing __has_feature(cxx_exceptions), or the __EXCEPTIONS define.

-Dimitry