Re: [musl] Detect qsort_r() support with preprocessor

[Quentin Rameau <quinq@fifth.space>]

Hi,

> > Hello musl devs,
> >
> > qsort_r() has been added to musl 1.2.3 and it has been backported to
> > the previous version of musl in Alpine. How can I detect whether this
> > function is available using the preprocessor?
> >
> > The community wiki advocates "testing" for feature support, which I
> > guess means compiling a test program like an autotools configure
> > script.
> 
> Guess why that is. It is more portable to do that way than to define new
> non-standard macros. The only macros musl will define are standard ones.
> 
> > Can we not just test for a macro instead? Have you considered
> > defining something like `__HAS_QSORT_R` to tell us directly that you
> > support it?
> >
> 
> Unless qsort_r() were part of a new release of POSIX (then you could
> look at _POSIX_VERSION), or a member of an option group (then you could
> look at the option group macro), not really.

Just as a note, qsort_r() has indeed been added to POSIX-next, so you'd
only need to ask for _POSIX_C_SOURCE with a value of 20XXXX, when it's
actually been released.