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

[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