Added configure test for const_cast<>(), and enabled it

for MSVC 5 and 6, and MinGW; use const_cast<>() in
wxConstCast if it is available.


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@19537 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

acinclude.m4

@@ -580,3 +580,21 @@ if test "$enable_largefile" != no; then
     AC_MSG_RESULT($wx_largefile)
 fi
 ])
+
+
+dnl Available from the GNU Autoconf Macro Archive at:
+dnl http://www.gnu.org/software/ac-archive/htmldoc/ac_cxx_const_cast.html
+dnl
+AC_DEFUN([AC_CXX_CONST_CAST],
+[AC_CACHE_CHECK(whether the compiler supports const_cast<>,
+ac_cv_cxx_const_cast,
+[AC_LANG_SAVE
+ AC_LANG_CPLUSPLUS
+ AC_TRY_COMPILE(,[int x = 0;const int& y = x;int& z = const_cast<int&>(y);return z;],
+ ac_cv_cxx_const_cast=yes, ac_cv_cxx_const_cast=no)
+ AC_LANG_RESTORE
+])
+if test "$ac_cv_cxx_const_cast" = yes; then
+  AC_DEFINE(HAVE_CONST_CAST,,[define if the compiler supports const_cast<>])
+fi
+])

aclocal.m4

@@ -593,6 +593,24 @@ if test "$enable_largefile" != no; then
 fi
 ])
 
+
+dnl Available from the GNU Autoconf Macro Archive at:
+dnl http://www.gnu.org/software/ac-archive/htmldoc/ac_cxx_const_cast.html
+dnl
+AC_DEFUN([AC_CXX_CONST_CAST],
+[AC_CACHE_CHECK(whether the compiler supports const_cast<>,
+ac_cv_cxx_const_cast,
+[AC_LANG_SAVE
+ AC_LANG_CPLUSPLUS
+ AC_TRY_COMPILE(,[int x = 0;const int& y = x;int& z = const_cast<int&>(y);return z;],
+ ac_cv_cxx_const_cast=yes, ac_cv_cxx_const_cast=no)
+ AC_LANG_RESTORE
+])
+if test "$ac_cv_cxx_const_cast" = yes; then
+  AC_DEFINE(HAVE_CONST_CAST,,[define if the compiler supports const_cast<>])
+fi
+])
+
 # Configure paths for GTK+
 # Owen Taylor     1997-2001
 

configure.in

@@ -1555,6 +1555,9 @@ WX_CPP_BOOL
 dnl check whether C++ compiler supports explicit keyword
 WX_CPP_EXPLICIT
 
+dnl check whether C++ compiler supports C++ casts
+AC_CXX_CONST_CAST
+
 dnl ---------------------------------------------------------------------------
 dnl Define search path for includes and libraries: all headers and libs will be
 dnl looked for in all directories of this path

include/wx/defs.h

@@ -222,8 +222,12 @@ typedef int wxWindowID;
 
 // check for explicit keyword support
 #ifndef HAVE_EXPLICIT
-    #if defined(__VISUALC__) && (__VISUALC__ >= 1200)
-        // VC++ 6.0 has explicit (what about the earlier versions?)
+    #if defined(__VISUALC__) && (__VISUALC__ >= 1100)
+        // VC++ 6.0 and 5.0 have explicit (what about the earlier versions?)
+        #define HAVE_EXPLICIT
+    #elif ( defined(__MINGW32__) || defined(__CYGWIN32__) ) \
+          && wxCHECK_GCC_VERSION(2, 95)
+        // GCC 2.95 has explicit, what about earlier versions?
         #define HAVE_EXPLICIT
     #elif defined(__BORLANDC__) && (__BORLANDC__ >= 0x0520)
         // BC++ 4.52 doesn't support explicit, CBuilder 1 does
@@ -240,6 +244,24 @@ typedef int wxWindowID;
     #define wxEXPLICIT
 #endif // HAVE_EXPLICIT/!HAVE_EXPLICIT
 
+// check for static/const/reinterpret_cast<>()
+#ifndef HAVE_STATIC_CAST
+    #if defined(__VISUALC__) && (__VISUALC__ >= 1100)
+        // VC++ 6.0 and 5.0 have C++ casts (what about the earlier versions?)
+        #define HAVE_CXX_CASTS
+    #elif ( defined(__MINGW32__) || defined(__CYGWIN32__) ) \
+          && wxCHECK_GCC_VERSION(2, 95)
+        // GCC 2.95 has C++ casts, what about earlier versions?
+        #define HAVE_CXX_CASTS
+    #endif
+#endif // HAVE_STATIC_CAST
+
+#ifdef HAVE_CXX_CASTS
+    #ifndef HAVE_CONST_CAST
+        #define HAVE_CONST_CAST
+    #endif
+#endif // HAVE_CXX_CASTS
+
 // ----------------------------------------------------------------------------
 // portable calling conventions macros
 // ----------------------------------------------------------------------------

include/wx/object.h

@@ -305,7 +305,11 @@ name##PluginSentinel  m_pluginsentinel;
 #define wxDynamicCastThis(className) \
  (IsKindOf(&className::sm_class##className) ? (className *)(this) : (className *)0)
 
+#ifdef HAVE_CONST_CAST
+#define wxConstCast(obj, className) const_cast<className *>(obj)
+#else
 #define wxConstCast(obj, className) ((className *)(obj))
+#endif
 
 
 #ifdef __WXDEBUG__

setup.h.in

@@ -150,6 +150,11 @@
  */
 #undef HAVE_EXPLICIT
 
+/*
+ * Define if your compiler supports const_cast<>()
+ */
+#undef HAVE_CONST_CAST
+
 /*
  * Use regex support
  */