Re: Wrong class export/visibility setting for shared libs in many Boost libs

From: Andrey Semashev (andrey.semashev_at_[hidden])
Date: 2021-02-02 15:24:05

On 2/2/21 5:09 PM, Peter Dimov via Boost wrote:
> Andrey Semashev wrote:
>> So, the bottom line, BOOST_PROGRAM_OPTIONS_DECL must be defined to:
>>
>> - BOOST_SYMBOL_EXPORT - on Windows, when the library is being built;
>> - BOOST_SYMBOL_IMPORT - on Windows, when the library is being consumed 
>> by user;
>> - BOOST_SYMBOL_VISIBLE - in any other case.
> 
> BOOST_SYMBOL_EXPORT is defined to BOOST_SYMBOL_VISIBLE on non-Windows in 
> order to make the third case unnecessary.

Oh, ok.

> Alexander suggests that on 
> macOS (but not Linux), it's also necessary to define BOOST_SYMBOL_IMPORT 
> to BOOST_SYMBOL_VISIBLE (instead of to nothing) on non-Windows. This 
> seems sensible.
> 
> In other words,
> 
> - BOOST_SYMBOL_EXPORT - when the library is being built;
> - BOOST_SYMBOL_IMPORT - when the library is being consumed by user.

Ok.