Re: Testing for compiler capabilities

[David Fang]

On Tue, 22 Aug 2006, Jan Engelhardt wrote:

> Hi David,
>
> I am afraid using -Werror does not work, it really needs -fvis.. on the
> command line:
>
> $ cat x.c
> int __attribute__((visibility("hidden"))) mx(void) { return 1337; }
> $ cc -c x.c -Wall -Werror
> (No error)
> $ cc -c x.c -Wall -Werror -fvisibility=hidden
> cc1: error: unrecognized option `-fvisibility=hidden'

Then the test is even simpler: compile an empty or trivial source file
with the same m4 test and replace -Werror with -fvisibility=hidden.
This is how I test for individual command-line options, where no
sophisticated diagnosis of the outcome is required (just success/fail).
HTH.

Fang