Re: On linux too (was Re: Base compilation broken on NetBSD)

[David Chisnall]

On 2 Nov 2012, at 09:05, Wolfgang Lux wrote:

> Do we need to define _XOPEN_SOURCE at all? In the headers on OS X I found 
> this comment:
>  Defining _POSIX_C_SOURCE or _XOPEN_SOURCE restricts the
>  available APIs to exactly the set of APIs defined by the
>  corresponding standard, based on the value defined.
> I guess (at least) other BSD based systems handle this macro similarly (I'm 
> too lazy to fire up a VM to check).

Yes, BSD libc uses the macro in this way.  Unfortunately, glibc uses it in the 
opposite way, and *only* exposes standard functionality if these macros are 
defined.  *BSD libc defaults to exposing everything, glibc defaults to exposing 
a very limited subset.  This gets doubly irritating on glibc because there are 
some pairs of functions that it is not possible to simultaneously expose, 
because some are POSIX and some are from BSD and the feature macros to expose 
one hide the other...

David

-- Send from my Jacquard Loom