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Re: Symbol management in header files
- From: Joseph Myers <joseph at codesourcery dot com>
- To: Florian Weimer <fweimer at redhat dot com>
- Cc: GNU C Library <libc-alpha at sourceware dot org>
- Date: Tue, 18 Oct 2016 15:57:32 +0000
- Subject: Re: Symbol management in header files
- Authentication-results: sourceware.org; auth=none
- References: <ec6e6362-f2e5-1c5b-19f0-32a37a3ade32@redhat.com>
On Tue, 18 Oct 2016, Florian Weimer wrote:
> However, TS 18661-1 added “iszero” to <math.h>, and this causes some build
> failures. Apparently, the main problem here is that it is a macro, which
> means it is not subject to scoping (which helps C++ in particular to cope with
> definitions of nextup/nextdown/fsub/canonincalize).
I think some build failures are inevitable with new features in headers;
applications that use _GNU_SOURCE simply need to be updated, just as
applications that defined their own getline function but didn't define
_GNU_SOURCE needed updating when getline was added to POSIX and so to the
default glibc API, and just as applications routinely need updating when
new GCC versions add new diagnostics or increase the default C and C++
standards used.
--
Joseph S. Myers
joseph@codesourcery.com