Re: [Acl-devel] [RFC] Add attribute visibility("default") to API functions

[Mike Frysinger]

On 11 Feb 2016 19:50, Yury Usishchev wrote:
> I am trying to make acl build with -fvisibility=hidden possible. For that API 
> functions (that are used externally)
> should be marked with __attribute__((visibility("default"))).

we already use hidden visibility in include/misc.h, so if we want to
invert the meaning, you'll need to update that too.

> --- a/include/acl.h
> +++ b/include/acl.h
> @@ -27,6 +27,17 @@
>  extern "C" {
>  #endif
>  
> +/* Define for visibility */
> +#if defined _WIN32 || defined __CYGWIN__
> + #define API_EXPORT
> +#else
> + #if __GNUC__ >= 4
> +  #define API_EXPORT __attribute__ ((visibility ("default")))
> + #else
> +  #define API_EXPORT
> + #endif
> +#endif

do not indent the # w/cpp.  that should always be in col 0.  e.g.
#if ...
# define ...
#else
# if ........

that said, i don't think this is the right route.  it'd be better imo:
(1) name it ACL_API_EXPORT
(2) just do in acl.h:
#ifndef ACL_API_EXPORT
# define ACL_API_EXPORT extern
#endif
(3) update config.h to define ACL_API_EXPORT to default visiblity
(4) update configure.ac to test for the flag directly -- we already have
the m4/visibility_hidden.m4 file in the codebase for this

since all our source files should be including config.h first, we
then know the macro will be defined before pulling in acl.h.

> --- a/libacl/acl_calc_mask.c
> +++ b/libacl/acl_calc_mask.c
>  
> -int
> +API_EXPORT int
>  acl_calc_mask(acl_t *acl_p)

there's no need to enumerate the definitions themselves.  just the
prototype is sufficient.
-mike

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