Re: wchar_t and -fshort-wchar

[Szabolcs Nagy <nsz@port70.net>]

* Sergey Dmitrouk <sdmitrouk@accesssoftek.com> [2015-02-18 12:53:37 +0200]:
> musl seems to build fine with -fshort-wchar, but when client applications

that cannot possibly work

wchar_t is assumed to be a unicode code point so short wchar_t is broken

> are built against musl all uses of wide character literals fail due to wide
> type defined internally by a compiler differs from the type of `wchar_t` in
> musl headers.
> 
> I faced this on ARM where `wchar_t` is defined as `unsigned int` by
> musl but it's `unsigned short` from compilers point of view.  I'd expect
> similar issues with other targets.
> 

http://arminfo.emea.arm.com/help/topic/com.arm.doc.ihi0042e/IHI0042E_aapcs.pdf

says

"The preferred type of wchar_t is unsigned int. However,
a virtual platform may elect to use unsigned short instead.
A platform standard must document its choice"

on musl/glibc/.. the platform standard is unsigned int

> Would it make sense to use `__WCHAR_TYPE__` for `wchar_t` when it's
> available (it's already used for i386, but for different reason)?
> Presumably, as compiler is responsible for creating wide literals, libc
> would better agree with it on the type.
> 
> Of course, this makes sense only if you intend to support builds with
> `-fshort-wchar` flag, which are not very common I believe.
> 

this is an abi change so a different loader path name etc should be
used then (you should create a new subarch in musl's terminology)

but i'm not sure how you plan to fix up mb to wc functions for
such a subarch..

> Best regards,
> Sergey