unicode.h and -Wcast-qual

[Stefan Huehner]

Hi,

i am currently trying to fix the -Wcast-qual warnings. In
include/wine/unicode.h there a 4 function:

static inline int strncmpW( const WCHAR *str1, const WCHAR *str2, int n)
static inline WCHAR *strchrW( const WCHAR *str, WCHAR ch )
static inline WCHAR *strrchrW( const WCHAR *str, WCHAR ch )
static inline WCHAR *strpbrkW( const WCHAR *str, const WCHAR *accept )

whose signatures forces us to discard the const of an parameter while
returning it as the function value. Compiling with -Wcast-qual gives
(correctly) this warning:

../../include/wine/unicode.h:218: warning: cast discards qualifiers from
pointer target type

Together these four functions account for a total of 1400 (!) warnings.

In samba_4 sourcecode i discovered the following macros, which are
apparently a hack but silences these warnings:

#define discard_const(ptr) ((void *)((intptr_t)(ptr)))
#define discard_const_p(type, ptr) ((type *)discard_const(ptr))

an crude proof of concept is attached as a patch.

I am not sure how portable this solution is...

Any comments are welcome...

Regards,
Stefan