[FFmpeg-cvslog] r21522 - trunk/configure

[Måns Rullgård]

Carl Eugen Hoyos <cehoyos at ag.or.at> writes:

> M?ns Rullg?rd <mans <at> mansr.com> writes:
>
>> >> +check_cc <<EOF && enable attribute_may_alias
>> >> +union { int x; } __attribute__((may_alias)) x;
>> >> +EOF
>> >
>> > How is this supposed to work?
>> > On all compilers I tested (gcc 2.95.3, icc 11.1), attribute may_alias is not
>> > supported, but configure happily reports it's working.
>> 
>> Then the compiler is silently ignoring it, and no harm is done.
>
> Please define silently.

Not reporting an error.

> Why is this attribute not set the same as all other attributes? We
> already know that is currently impossible for configure to correctly
> test them.

Some compilers claim to be gcc without supporting all attributes and
do fail with an error if unknown attributes are used.  We must test
for these.

What do you suggest instead?

-- 
M?ns Rullg?rd
mans at mansr.com