stdnoreturn ideas [was: [PATCH] openat-die: use _Noreturn markup]

[Eric Blake]

On 07/30/2014 10:22 PM, Eric Blake wrote:
> On 07/30/2014 09:53 PM, Eric Blake wrote:
> 
>>
>> Meanwhile, './gnulib-tool --test stdnoreturn' is failing on cygwin, so

> 
> Looks like the cygwin headers are broken for misusing 'noreturn' instead
> of __noreturn__ inside __attribute__; something that is easier to patch
> in cygwin than work around in gnulib.

I wonder if gnulib could work around this failure by having the
replacement <stdnoreturn.h> do a #include of all broken headers prior to
an #include_next of the real <stdnoreturn.h>; except that
<stdnoreturn.h> only needs to define macros, and the gnulib code for
probing how to do include_next depends on the system header having
non-comment non-macro contents (so that the preprocessor output is not
entirely elided).

Anyways, determining the set of broken headers seems like a lot of work;
it may be just simpler to do a configure probe whether any headers
appear to be broken, and have <stdnoreturn.h> behave like it does for
MSVC (that is, be a no-op with no definition of 'noreturn' because the
system headers are buggy).  I'll probably prepare a gnulib patch along
these lines, because it may be a while before the next cygwin release
that includes my patches for the broken headers.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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