Re: [Boost-build] gcc visibility support

Subject: Re: [Boost-build] gcc visibility support
From: John Maddock (boost.regex_at_[hidden])
Date: 2010-08-24 04:14:50

> a) visibility is supported in version 4+ compilers.  What syntax does one 
> use to specify that that the above should only apply to these compilers.
>
> b) If one is building a static library, presuably the above shouldn't be 
> included (though it probably does no harm).  How does this modify the 
> above syntax?
>
> c) The cygwin system I use to test has gcc-4.3.4 installed.  BUT, the 
> usage of -fvisibility=hidden evokes a compile time warning for file.  The 
> warning says that visibility is not supported on this build - which 
> presumably is cygwin. So the above would also have to be conditioned upon 
> the fact that cygwin is not being used.

The way I fixed this up for Boost.Math was to use the check-target-builds 
rule to test to see if -fvisibility-hidden was supported, and then to use it 
only if it is - take a look at libs/math/build/Jamfile and 
libs/math/config/Jamfile to see how this works.

HTH, John.