Re: [boost] [Variant] [BGL] Variant<edge_descriptor, edge_descriptor> is not EqualityComparable

Subject: Re: [boost] [Variant] [BGL] Variant<edge_descriptor, edge_descriptor> is not EqualityComparable
From: Stefan Strasser (strasser_at_[hidden])
Date: 2009-11-12 09:44:51

Am Thursday 12 November 2009 12:05:33 schrieb Cosimo Calabrese:
>
> using namespace std::rel_ops;
>
> to add the generic operator!=(), but the compiler doesn't find it, the
> compiler error is the same.

using namespace std::rel_ops;
(or your free function, it's the same thing) needs to be before the point 
operator != is used.
I didn't realize this because GCC accepts it if it's there at the point of 
instantiation, but other compilers don't.
so try to put it at the beginning of the file, before including the graph 
library.

this is only a workaround though. the graph library shouldn't use operator!= 
if its only requirement on the type is EqualityComparable. have you filed a 
bug ticket?