Change boost::tuple::ignore to initialisation rather than assignment to allow pre-compiled headers

[Peter Myerscough-Jackopson <peter.myerscough-jackopson@…>]

In the boost tuple library, there is a variable called ignore that can be used in calls to boost::tie(...). Under C++Builder 2007 it is not possible to generate pre-compiled headers when including the appropriate headers to use boost::tie because the ignore variable is assigned on construction using the =operator rather than constructed/initialised. Although this may be about optimising build performance, and I am using an older compiler, I don't think I am requesting a negative change.

--- boost/tuple/detail/tuple_basic.hpp (Revision 46808)
+++ boost/tuple/detail/tuple_basic.hpp (working copy)
@@ -665,7 +665,7 @@
} // namespace detail

// "ignore" allows tuple positions to be ignored when using "tie".
---detail::swallow_assign const ignore = detail::swallow_assign();
+++detail::swallow_assign const ignore( detail::swallow_assign() );

// ---------------------------------------------------------------------------
// The call_traits for make_tuple

I hope this is accepted,

Yours,

Peter MJ

[Steven Watanabe]

This doesn't do what you think.

detail::swallow_assign const ignore( detail::swallow_assign() );

is a function declaration.

[Steven Watanabe]

(In [62684]) Use an inline function instead of a static object for boost::tuples::ignore, avoiding problems with the ODR and Borland precompiled headers. Fixes #2656