added wxEXPLICIT macro

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@16194 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

acinclude.m4

@@ -144,6 +144,53 @@ AC_DEFUN([WX_CPP_BOOL],
   fi
 ])
 
+dnl ---------------------------------------------------------------------------
+dnl WX_CPP_EXPLICIT checks whether the C++ compiler support the explicit
+dnl keyword and defines HAVE_EXPLICIT if this is the case
+dnl ---------------------------------------------------------------------------
+
+AC_DEFUN([WX_CPP_EXPLICIT],
+[
+  AC_CACHE_CHECK([if C++ compiler supports the explicit keyword],
+                 wx_cv_explicit,
+  [
+    AC_LANG_SAVE
+    AC_LANG_CPLUSPLUS
+
+    dnl do the test in 2 steps: first check that the compiler knows about the
+    dnl explicit keyword at all and then verify that it really honours it
+    AC_TRY_COMPILE(
+      [
+        class Foo { public: explicit Foo(int) {} };
+      ],
+      [
+        return 0;
+      ],
+      [
+        AC_TRY_COMPILE(
+            [
+                class Foo { public: explicit Foo(int) {} };
+                static void TakeFoo(const Foo& foo) { }
+            ],
+            [
+                TakeFoo(17);
+                return 0;
+            ],
+            wx_cv_explicit=no,
+            wx_cv_explicit=yes
+        )
+      ],
+      wx_cv_explicit=no
+    )
+
+    AC_LANG_RESTORE
+  ])
+
+  if test "$wx_cv_explicit" = "yes"; then
+    AC_DEFINE(HAVE_EXPLICIT)
+  fi
+])
+
 dnl ---------------------------------------------------------------------------
 dnl a slightly better AC_C_BIGENDIAN macro which allows cross-compiling
 dnl ---------------------------------------------------------------------------

aclocal.m4

@@ -156,6 +156,53 @@ AC_DEFUN([WX_CPP_BOOL],
   fi
 ])
 
+dnl ---------------------------------------------------------------------------
+dnl WX_CPP_EXPLICIT checks whether the C++ compiler support the explicit
+dnl keyword and defines HAVE_EXPLICIT if this is the case
+dnl ---------------------------------------------------------------------------
+
+AC_DEFUN([WX_CPP_EXPLICIT],
+[
+  AC_CACHE_CHECK([if C++ compiler supports the explicit keyword],
+                 wx_cv_explicit,
+  [
+    AC_LANG_SAVE
+    AC_LANG_CPLUSPLUS
+
+    dnl do the test in 2 steps: first check that the compiler knows about the
+    dnl explicit keyword at all and then verify that it really honours it
+    AC_TRY_COMPILE(
+      [
+        class Foo { public: explicit Foo(int) {} };
+      ],
+      [
+        return 0;
+      ],
+      [
+        AC_TRY_COMPILE(
+            [
+                class Foo { public: explicit Foo(int) {} };
+                static void TakeFoo(const Foo& foo) { }
+            ],
+            [
+                TakeFoo(17);
+                return 0;
+            ],
+            wx_cv_explicit=no,
+            wx_cv_explicit=yes
+        )
+      ],
+      wx_cv_explicit=no
+    )
+
+    AC_LANG_RESTORE
+  ])
+
+  if test "$wx_cv_explicit" = "yes"; then
+    AC_DEFINE(HAVE_EXPLICIT)
+  fi
+])
+
 dnl ---------------------------------------------------------------------------
 dnl a slightly better AC_C_BIGENDIAN macro which allows cross-compiling
 dnl ---------------------------------------------------------------------------

configure.in

@@ -1406,6 +1406,9 @@ WX_CPP_NEW_HEADERS(, AC_DEFINE(wxUSE_IOSTREAMH))
 dnl check whether C++ compiler supports bool built-in type
 WX_CPP_BOOL
 
+dnl check whether C++ compiler supports explicit keyword
+WX_CPP_EXPLICIT
+
 dnl ---------------------------------------------------------------------------
 dnl Define search path for includes and libraries: all headers and libs will be
 dnl looked for in all directories of this path

docs/changes.txt

@@ -171,6 +171,7 @@ wxBase:
 - added static wxFontMapper::Get() accessor (use of wxTheFontMapper is now
   deprecated)
 - added wxShutdown() function (Marco Cavallini)
+- added wxEXPLICIT macro
 
 Unix (Base/GUI):
 

docs/latex/wx/function.tex

@@ -67,6 +67,7 @@ the corresponding topic.
 \helpref{wxError}{wxerror}\\
 \helpref{wxExecute}{wxexecute}\\
 \helpref{wxExit}{wxexit}\\
+\helpref{wxEXPLICIT}{wxexplicit}\\
 \helpref{wxFAIL\_MSG}{wxfailmsg}\\
 \helpref{wxFAIL}{wxfail}\\
 \helpref{wxFatalError}{wxfatalerror}\\
@@ -2100,6 +2101,13 @@ The clipboard must have previously been opened for this call to succeed.
 
 \section{Miscellaneous functions}\label{miscellany}
 
+\membersection{wxEXPLICIT}\label{wxexplicit}
+
+{\tt wxEXPLICIT} is a macro which expands to the C++ {\tt explicit} keyword if
+the compiler supports it or nothing otherwise. Thus, it can be used even in the
+code which might have to be compiled with an old compiler without support for
+this language feature but still take advantage of it when it is available.
+
 \membersection{::wxNewId}\label{wxnewid}
 
 \func{long}{wxNewId}{\void}

include/wx/defs.h

@@ -210,7 +210,7 @@ typedef short int WXTYPE;
 // window id is unsigned, so we must always do the cast before comparing them
 // (or else they would be always different!). Usign wxGetWindowId() which does
 // the cast itself is recommended. Note that this type can't be unsigned
-// because -1 is a valid (and largely used) value for window id.
+// because wxID_ANY == -1 is a valid (and largely used) value for window id.
 typedef int wxWindowID;
 
 // ----------------------------------------------------------------------------
@@ -229,6 +229,20 @@ typedef int wxWindowID;
     #define wxUSE_NESTED_CLASSES    0
 #endif
 
+// check for explicit keyword support
+#ifndef HAVE_EXPLICIT
+    // TODO: add more compiler tests here
+    #if defined(__VISUALC__) && (__VISUALC__ > 1020)
+        #define HAVE_EXPLICIT
+    #endif
+#endif // !HAVE_EXPLICIT
+
+#ifdef HAVE_EXPLICIT
+    #define wxEXPLICIT explicit
+#else // !HAVE_EXPLICIT
+    #define wxEXPLICIT
+#endif // HAVE_EXPLICIT/!HAVE_EXPLICIT
+
 // ----------------------------------------------------------------------------
 // portable calling conventions macros
 // ----------------------------------------------------------------------------

setup.h.in

@@ -129,6 +129,11 @@
  */
 #undef HAVE_BOOL
 
+/*
+ * Define if your compiler supports the explicit keyword
+ */
+#undef HAVE_EXPLICIT
+
 /*
  * Use regex support
  */