Re: Testing for GCC-like attributes and compiler switches

[Andrew W. Nosenko]

2010/10/16 Andrew W. Nosenko <address@hidden>:
> 2010/10/15 Václav Haisman <address@hidden>:
>> Hi.
>>
>> I am having difficulty testing for compiler features like
>> __declspec(dllimport) and switches like -Wall or -Werror.
>>
>> The problem has started like this. I wanted to test compiler for
>> __declspec(dllimport) (for Windows) and if that fails for
>> __attribute__((visibility("default"))) (for *nix/GCC). With GCC this works
>> because it does support both, it supports __declspec(dllimport) even outside
>> Windows. But with e.g. Clang, this fails. Clang accepts the code of the
>> test-case with just warning like:
>>
>> "conftest.cpp:20:12: warning: 'dllexport' attribute ignored"
>>
>> The test-case passes but the compiler does not support the feature.
>
> Can you inspect the resulting object file somehow (sorry, I'm not a
> Windows guru)?  For example by trying to use result like the
> program-customer intended to do.  I.e. in the case of windows try to
> build trivial dll, the program-user and link them together (and,
> possible, run)?
>

BTW: why you need at all to pass __dllexport on non-Windows platform
(and therefore bother whether Unix-only compiler under [again] Unix
igrores it?

Similar about "visibility default".  OK, "visibility hidden" could be
useful under some circumstances and for some goals.  But "default"?
(Assuming that you didn't bring all source into "hidden" or something
like that.)

-- 
Andrew W. Nosenko <address@hidden>