Re: __xmknod, __sysv_signal

[Rob Landley <rob@landley.net>]

On 05/06/14 22:17, Rich Felker wrote:
> On Tue, May 06, 2014 at 11:55:48AM -0500, M Farkas-Dyck wrote:
>> What is musl's general policy on ABI compat? The FAQ says solely that
>> "musl aims for a degree of feature-compatibility", not what degree. Is
>> full binary compatibility with glibc the goal?
> 
> While I don't think it's spelled out anywhere, the hope is to make it
> so any strictly conforming POSIX program build against glibc also
> works with musl dropped in. Programs using extensions that musl also
> provides should work too. Programs using glibc features that musl does
> not provide, or depending on glibc bugs, are not intended to be
> supported.
> 
>> If we mean to include such, we ought to choose where to keep the code first.
> 
> Similar things are scattered here and there; see the junk in
> src/ctype.


Given that:

#ifdef __MUSL__
#include <gnuisms.h>
#endif

is off the table because musl is the platonic ideal C library, anonymous
and infinite, and the idea of having musl-specific idiosynrasies that
aren't necessarily considered the default (let alone building software
for other libraries with 90% market share and wildly different behavior)
will never come up in practice...

There's a gnu extension called #include_next that lets you have a second
set of headers inserted before the first set. It is, of course, a gnu
extension.

The library side seems easy enough to deal with via some sort of -lcrap
added to the build, if you don't want it in libc itself.

Or you could have a "./configure --legacy" to selectively enable this
sort of stuff in libc.so and the headers, and then require people to use
something like autoconf to determine whether or not this instance of
libc was built with that because a #define would be coddling them.

Rob