C++ PATCH: PR 20599 (1/3)

[Howard Hinnant]

On Sep 25, 2006, at 9:35 AM, Gabriel Dos Reis wrote:

> | Without a feature-test macro, the library author will have to supply
> | two separate implementations, and tell their clients:  Use this
> | version over here if you enable this feature, else use that version
> | over there.
>
> No.  The *library author* defines the macros that guard its uses of
> the specific GCC extensions.  He/she does not need to provide two
> separate implementations.

Ah, sorry, I misunderstood your user interface:

g++ my_source.cpp -D _STD_RVALUE_REF -D _STD_VARIADIC_TEMPLATES -D  
_STD_STATIC_ASSERT -D BOOST_RVALUE_REFS -D BOOST_VARIADIC_TEMPLATES - 
D BOOST_STD_STATIC_ASSERT -D ACME_RVALUE_REFS_ON -D  
ACME_USE_VARIADIC_TEMPLATES -D ACME_USE_STATIC_ASSERT - 
enable_rvalue_refs -enable_variadic_templates -enable_static_assert - 
lboost -lAcme

I would prefer something more like:

g++ my_source.cpp -enable_rvalue_refs -enable_variadic_templates - 
enable_static_assert -lboost -lAcme

I.e. the main difference is that we are discussing is whether or not  
gcc standardizes the spelling of these feature test macros, and  
supplies them automatically.

-Howard