Boost C++ Libraries: Ticket #1791: fix warning on MSVC warning level 4

attachment set

Stephan — Tue, 08 Apr 2008 19:34:40 GMT

attachment → lexical_cast_warning.patch

nasonov — Tue, 22 Apr 2008 13:21:38 GMT

As you may guess, the return statement was added to supress a warning.

Can you please discusss possible workarounds on boost-devel? I don't have time, sorry.

Off the top of my head:

template<class R, class E> R throw_exception_impl(E const & e) {

throw_exception(e);

I expect a lot of workarounds around this place return R();

}

and then

throw_exception_impl<Target>(bad_lexical_cast(typeid(Source), typeid(Target)));

-- Alex

Stephan — Tue, 10 Jun 2008 15:56:22 GMT

Replying to nasonov:

As you may guess, the return statement was added to supress a warning.

Can you please discusss possible workarounds on boost-devel? I don't have time, sorry.

Sure: Here is what Paul came up with:

#if (defined _MSC_VER)
# pragma warning( push )
# pragma warning( disable : 4702 ) : unreachable code
#endif
throw_exception(bad_lexical_cast(typeid(Source), typeid(Target)));
return Target(); // normally never reached (throw_exception)
#if (defined _MSC_VER)
# pragma warning( pop )
#endif

which looks fine for me.

Thanks,

Stephan

Sun, 05 Oct 2008 17:31:42 GMT

Attached is a patch that pragmas out this warning, silencing the warnings that i see on VC9.

The patch is slightly different to the previously suggested patch, in that (on VC9 at least), the pragma has to surround the whole function rather than just the return line in order to actually silence the warning.

attachment set

Sun, 05 Oct 2008 17:32:13 GMT

attachment → lexical_cast.patch

sdiederich — Mon, 01 Dec 2008 11:50:50 GMT

Ping. Warning is not yet patched in trunk, or release branch, and was therefore not in 1.37. Richard's patch looks good to me. Any chance we can see this included in 1.38?

attachment set

Sat, 30 May 2009 15:14:52 GMT

attachment → lexical_cast2.patch

version, milestone changed

Sat, 30 May 2009 15:16:04 GMT

version Boost 1.35.0 → Boost Development Trunk
milestone To Be Determined → Boost 1.40.0

milestone changed

nasonov — Sat, 12 Sep 2009 21:34:50 GMT

milestone Boost 1.40.0 → Boost 1.41.0

status changed; resolution set

nasonov — Sat, 12 Sep 2009 21:47:28 GMT

status new → closed
resolution → fixed

(In [56158]) Fix #1791 (fix warning on MSVC warning level 4) and undo r34801 (some "rewording" to avoid spurious level 4 warnings with VC7.1 and VC8).