can't you just infer musl from the relatively small ? #if defined(__linux__) && (!defined(__BIONIC__) && !defined(__GLIBC__) && whatever ulibc is if you haven't given up on that yet) #define __MUSL__ #endif
? On Mon, Aug 28, 2017 at 10:35 PM, Rob Landley <r...@landley.net> wrote: > The point of chrt is to use the sched_setscheduler() syscall to change a > PID's scheduler category (by default making it a realtime process), but > the musl-libc maintainer decided he didn't like that system call and > changed the wrapper to return -ENOSYS instead of making the system call: > > https://git.musl-libc.org/cgit/musl/commit?id=1e21e78bf7a5c24c217446d8760be7b7188711c2 > > Unfortunately musl-libc has a policy that musl is never wrong and thus > it doesn't provide a #define __MUSL__ that you can test against to work > around this kind of breakage, the way every other libc does. > > http://wiki.musl-libc.org/wiki/FAQ#Q:_why_is_there_no_MUSL_macro_.3F > > I did a quick stab at replacing sched_setscheduler() with a wrapper that > calls syscall(NR_sched_setscheduler) but that musl commit broke _all_ > the sched functions, sched_get_priority_max() and so on. I'd have to > wrap all of them, even on systems that provide non-broken wrappers for > the Linux syscall. > > This is why we have the TOYBOX_MUSL_NOMMU_IS_BROKEN config symbol, for a > similar case where for 20 years nommu linux let you tell if you were > building for a system with mmu or without it by a simple compile time > probe: build a hello world that links against fork(); if it's not there > it's a nommu system. Rich decided he didn't like that, and provided a > broken fork() (always returns -ENOSYS) for nommu systems so you can't > tell at compile time whether it's mmu or not. > > I'm trying to figure out if I should just leave chrt broken on musl and > add a FAQ entry about it. If there was an #ifdef __MUSL__ I'd have the > build produce a warning and the runtime produce a message, but of course > there isn't... > > Rob > _______________________________________________ > Toybox mailing list > Toybox@lists.landley.net > http://lists.landley.net/listinfo.cgi/toybox-landley.net -- Elliott Hughes - http://who/enh - http://jessies.org/~enh/ Android native code/tools questions? Mail me/drop by/add me as a reviewer. _______________________________________________ Toybox mailing list Toybox@lists.landley.net http://lists.landley.net/listinfo.cgi/toybox-landley.net
