fix warning on MSVC warning level 4

[Stephan]

Attached patch fixes a warning in MSVC 8 on warning level 4 by removing a return statement after a throw "call"

[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.

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]

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

[Richard Webb <richard.webb@…>]

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.

[sdiederich]

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?

[nasonov]

(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).