Re: [boost] Concept based overloading and the ODR

From: Steven Watanabe (watanabesj_at_[hidden])
Date: 2008-07-11 14:50:27

AMDG

David Abrahams wrote:
> I fully agree.  My point was that he's got a problem that we're not
> solving by simply insisting on ODR-friendly practices.
>
>   
>> The only safe way to allow replacement of a library function that I
>> know of is to use a macro, since this can be set globally.
>>     
>
> Many people think macros are too ODR-prone also.
>   

What other ways are there to solve it?  I realize that macros are still
dangerous but they are better than any alternative that I know--other
than only allowing customization through specializations that involve
at least one user defined type.

Is there any known way of automatically triggering a link error if macros
are defined differently in different translation units?  I can think of 
a manual
way:

a.cpp:

void BOOST_PP_CAT(a_cpp_compatibility, OPTIONS_ENCODED_AS_IDENTIFIER)() {}

b.cpp

static void test_a_cpp_compatibility() {
    BOOST_PP_CAT(a_cpp_compatibility, OPTIONS_ENCODED_AS_IDENTIFIER)();
}

In Christ,
Steven Watanabe