On 17/02/2017 10:17, Laszlo Ersek wrote:
> Of course, *if* that other C library, and the Curses implementation,
> claim compatibility with glibc as far as _GNU_SOURCE goes, *then* I
> fully agree with you. (IOW, it depends on the condition that you
> formulated above, "if musl wants to support _GNU_SOURCE".)
They at least try, since their features.h supports it.
> Same for ncurses -- do they aim at SUSv2 conformance, or do they intend
> to consider _GNU_SOURCE specifically?
Well, ncurses is a GNU project so I suppose they mostly care about
whatever Autoconf does. And indeed Autoconf does have some special
casing for -D_XOPEN_SOURCE=500:
AC_CACHE_CHECK([whether _XOPEN_SOURCE should be defined],
[ac_cv_should_define__xopen_source],
[ac_cv_should_define__xopen_source=no
AC_COMPILE_IFELSE(
[AC_LANG_PROGRAM([[
#include <wchar.h>
mbstate_t x;]])],
[],
[AC_COMPILE_IFELSE(
[AC_LANG_PROGRAM([[
#define _XOPEN_SOURCE 500
#include <wchar.h>
mbstate_t x;]])],
[ac_cv_should_define__xopen_source=yes])])])
test $ac_cv_should_define__xopen_source = yes &&
AC_DEFINE([_XOPEN_SOURCE], [500])
If musl needs _XOPEN_SOURCE for wchar.h, then it would be worth working
around in QEMU. If it's just happening with ncurses, however, it'd be a
musl bug, which should be fixed in musl or worked around in ncurses.
Chad, can you check whether the programs below fails with musl:
/* First program */
#define _GNU_SOURCE
#include <wchar.h>
mbstate_t x;
/* Second program */
#include <wchar.h>
mbstate_t x;
/* Third program */
#define _XOPEN_SOURCE 500
#include <wchar.h>
mbstate_t x;
Just compile them with "gcc foo.c -O2".
Thanks,
Paolo
