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

[Gabriel Dos Reis]

"Peter Dimov" <pdimov@mmltd.net> writes:

[...]

| > you can use that library code only if GCC gets to the point of
| > compiling it -- which can't happen when the compiler does not
| > understand the option. Concretely, the feature-test is illusory
| > unless you also change how
| > GCC handls unrecognized command-line options.
| 
| But the library could support both modes, with or without the
| option.

I do not disagree with that.  However, it could be  practically used
in the extended mode only if you know in advance that the compiler
supports it (because you have to explicit ask for it), which means 
you're actually in the position of supplying the guarding macro.

-- Gaby