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

-------------- next part --------------
Index: configure.ac
===================================================================
RCS file: /home/wine/wine/configure.ac,v
retrieving revision 1.366
diff -u -r1.366 configure.ac
--- configure.ac	20 Jun 2005 15:52:16 -0000	1.366
+++ configure.ac	20 Jun 2005 20:16:14 -0000
@@ -1276,6 +1276,7 @@
 AC_C_INLINE
 AC_CHECK_TYPES([mode_t, off_t, pid_t, size_t, ssize_t, long long, fsblkcnt_t, fsfilcnt_t])
 AC_CHECK_TYPES([sigset_t],,,[#include <signal.h>])
+AC_CHECK_TYPES(intptr_t)
 
 AC_CACHE_CHECK([whether linux/input.h is for real],
 	wine_cv_linux_input_h,
Index: include/wine/unicode.h
===================================================================
RCS file: /home/wine/wine/include/wine/unicode.h,v
retrieving revision 1.32
diff -u -r1.32 unicode.h
--- include/wine/unicode.h	28 Apr 2005 12:01:37 -0000	1.32
+++ include/wine/unicode.h	20 Jun 2005 20:16:14 -0000
@@ -31,6 +31,17 @@
 #define WINE_UNICODE_API DECLSPEC_IMPORT
 #endif
 
+#include <stdint.h>
+#include <config.h>
+
+#ifdef HAVE_INTPTR_T
+#define discard_const(ptr) ((void *)((intptr_t)(ptr)))
+#else
+#define discard_const(ptr) ((void *)(ptr))
+#endif
+#define discard_const_p(type, ptr) ((type *)discard_const(ptr))
+
+
 /* code page info common to SBCS and DBCS */
 struct cp_info
 {
@@ -215,20 +226,20 @@
 
 static inline WCHAR *strchrW( const WCHAR *str, WCHAR ch )
 {
-    for ( ; *str; str++) if (*str == ch) return (WCHAR *)str;
+    for ( ; *str; str++) if (*str == ch) return discard_const_p(WCHAR, str);
     return NULL;
 }
 
 static inline WCHAR *strrchrW( const WCHAR *str, WCHAR ch )
 {
     WCHAR *ret = NULL;
-    for ( ; *str; str++) if (*str == ch) ret = (WCHAR *)str;
+    for ( ; *str; str++) if (*str == ch) ret = discard_const_p(WCHAR, str);
     return ret;
 }
 
 static inline WCHAR *strpbrkW( const WCHAR *str, const WCHAR *accept )
 {
-    for ( ; *str; str++) if (strchrW( accept, *str )) return (WCHAR *)str;
+    for ( ; *str; str++) if (strchrW( accept, *str )) return discard_const_p(WCHAR, str);
     return NULL;
 }
 
@@ -263,7 +274,7 @@
 static inline WCHAR *memchrW( const WCHAR *ptr, WCHAR ch, size_t n )
 {
     const WCHAR *end;
-    for (end = ptr + n; ptr < end; ptr++) if (*ptr == ch) return (WCHAR *)ptr;
+    for (end = ptr + n; ptr < end; ptr++) if (*ptr == ch) return discard_const_p(WCHAR, ptr);
     return NULL;
 }
 
@@ -271,7 +282,7 @@
 {
     const WCHAR *end, *ret = NULL;
     for (end = ptr + n; ptr < end; ptr++) if (*ptr == ch) ret = ptr;
-    return (WCHAR *)ret;
+    return discard_const_p(WCHAR , ret);
 }
 
 static inline long int atolW( const WCHAR *str )