Re: [Boost-users] [uuid] to string problem

Subject: Re: [Boost-users] [uuid] to string problem
From: John Dlugosz (JDlugosz_at_[hidden])
Date: 2010-05-12 15:19:43

> Providing a function template parameter explicitly will disable ADL.
> 

I just looked through N3092, and that is not (no longer?) the case.  

        f(x);  // uses ADNL
        (f)(x);  // suppresses ADNL
        f<int>(x);  // still uses ADNL.

§14.2 (temp.names, if you want to try finding the corresponding sections in an older standard) defines 'template-id' such that f<int> is one.

§5.1.1 (expr.prim.general) defines a 'template-id' to be a 'unqualified-id'.

§3.4.2 (basic.lookup.argdep) states 

        "When the postfix-expression in a function call (5.2.2) is an unqualified-id, other namespaces not considered during the usual unqualified lookup (3.4.1) may be searched, and in those namespaces, namespace-scope friend function declarations (11.4) not otherwise visible may be found. These modifications to the search depend on the types of the arguments (and for template template arguments, the namespace of the template argument).

I can't access my copy of the official C++98 standard anymore because of stupid DRM stuff in Acrobad Reader, and the paper copy is much harder to grep and has been consigned to a box somewhere for a few years.  But maybe someone knows if that has changed and was indeed not the case before, or if the compiler is actually buggy now for not doing it?

So, it is "the future" even if it is not the present.  Default arg should still work, so making to_string be a template for different return types should be something that works as well as a single function now, is accessible the hard way if you want a different form, and will work better in the future.


--John





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