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

[Jacek Caban]

Stefan Huehner wrote:
> I am not sure how portable this solution is...

To make it portable you can use ULONG_PTR instead
of intptr_t.

Jacek

[Jelmer Vernooij]

Hi,

On Mon, Jun 20, 2005 at 10:26:32PM +0200, Stefan Huehner wrote about 'unicode.h and -Wcast-qual':
> Hi,
> i am currently trying to fix the -Wcast-qual warnings. In
> include/wine/unicode.h there a 4 function:
> 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...
> It should be fairly portable as it works on all of the platforms Samba runs
> on, which includes odd ones such as AIX, Cray, various BSDs, solaris..

Cheers,

Jelmer
-- 
Jelmer Vernooij <jelmer(a)samba.org> - http://jelmer.vernstok.nl/

[David Laight]

On Mon, Jun 20, 2005 at 10:26:32PM +0200, Stefan Huehner wrote:
> 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))

Or:

static inline void *deconst(const void *p)
{
    return ((const char *)p - (const char *)0) + (char *)0;
}

	David

-- 
David Laight: david(a)l8s.co.uk