This is the mail archive of the
libc-alpha@sourceware.org
mailing list for the glibc project.
Re: compiler standards (and/or min gcc version) supported with installedheaders ?
On 01/04/2013 05:09 PM, Carlos O'Donell wrote:
[...]
Thanks for putting this together and driving concensus here.
Thanks for the review, I'm appending a version that has your changes in it.
I assume your goal is to add this to the concensus section on the wiki
and to add it to INSTALL or some other file in the project?
I wanted to add this to the wiki but haven't figured out where exactly.
* glibc needs a recent GCC compiler version to build itself (right now
"requires GCC version 4.3 or newer to build; GCC 4.6 is
recommended.")
* Userland applications and libraries that use glibc's headers and
libraries can be built by a variety of compilers.
The following community concensus applies to glibc's headers:
- The installed headers shall work with any compiler that:
* supports at least ISO C 90 (or C++98)
* supports the type "long long"
- GCC version 2.95.3 is the oldest supported compiler, with some
architectures requiring more recent versions.
- GCC versions older than 2.95.3 may still be used, but no
optimizations or special allowances are made for them.
- Compiler dependent code shall be protected by feature test
macros. For example the various GCC __builtin_X functions can be
used but need to be properly guarded.
- The glibc header files might include special optimizations for
newer compiler versions which might not be available for older
compilers
- The header files for glibc use GCC 4.3 as baseline for
optimizations
- Support for other compilers besides GCC might need extra patches
which are welcome to be submitted for inclusion glibc
- For headers shared with gnulib, other conditions do apply (the
requirements from gnulib to support even older compilers)
To support different compilers, we would ideally not test - as today -
for a specific GCC version but for a specific feature.
So, instead of __GNUC_PREREQ(x,y) to check for a specific version in
some header file, the advise is to add a macro to features.h, like
__GLIBC_HAVE_BUILTIN_COMPLEX and use that - and that macro definition
is dependend on compiler versions.
--
Andreas Jaeger aj@{suse.com,opensuse.org} Twitter/Identica: jaegerandi
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany
GF: Jeff Hawn,Jennifer Guild,Felix Imendörffer,HRB16746 (AG Nürnberg)
GPG fingerprint = 93A3 365E CE47 B889 DF7F FED1 389A 563C C272 A126