document wx[US]Char and wxStringCharType typedefs; in docs for wxS() specify better that it makes wide strings under UTF16 builds and narrow strings under UTF8 builds

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@57064 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

interface/wx/chartype.h

@@ -11,8 +11,8 @@
 
 /**
     This macro can be used with character and string literals (in other words,
-    @c 'x' or @c "foo") to automatically convert them to Unicode in Unicode
+    @c 'x' or @c "foo") to automatically convert them to wide strings in Unicode
-    builds of wxWidgets. This macro is simply returns the value passed to it
+    builds of wxWidgets. This macro simply returns the value passed to it
     without changes in ASCII build. In fact, its definition is:
 
 @code
@@ -23,22 +23,25 @@
 #endif
 @endcode
 
-    @see @ref overview_unicode
+    @see @ref overview_unicode, wxS()
 
     @header{wx/chartype.h}
 */
 #define wxT(string)
 
 /**
-    wxS is macro which can be used with character and string literals to either
+    wxS is macro which can be used with character and string literals (in other words,
-    convert them to wide characters or strings in @c wchar_t-based Unicode
+    @c 'x' or @c "foo") to either convert them to wide characters or wide strings
-    builds or keep them unchanged in UTF-8 builds. The use of this macro is
+    in @c wchar_t-based (UTF-16) builds or keep them unchanged in @c char-based
-    optional as the translation will always be done at run-time even if there
+    (UTF-8) builds.
-    is a mismatch between the kind of the literal used and string or character
-    type used in the current build, but using it can be beneficial in
-    performance-sensitive code to do the conversion at compile-time instead.
 
-    @see wxT()
+    The use of this macro is optional as the translation will always be done at
+    run-time even if there is a mismatch between the kind of the literal used
+    and the string or character type used in the current build.
+    However using it can be beneficial in <b>performance-sensitive code</b> to
+    do the conversion at compile-time instead.
+
+    @see @ref overview_unicode, wxT()
 
     @header{wx/chartype.h}
 */
@@ -56,4 +59,39 @@
 */
 #define _T(string)
 
+/**
+    wxChar is defined to be
+    - @c char when <tt>wxUSE_UNICODE==0</tt>
+    - @c wchar_t when <tt>wxUSE_UNICODE==1</tt> (the default).
+*/
+typedef wxUSE_UNICODE_dependent wxChar;
+
+/**
+    wxSChar is defined to be
+    - <tt>signed char</tt> when <tt>wxUSE_UNICODE==0</tt>
+    - @c wchar_t when <tt>wxUSE_UNICODE==1</tt> (the default).
+*/
+typedef wxUSE_UNICODE_dependent wxSChar;
+
+/**
+    wxUChar is defined to be
+    - <tt>unsigned char</tt> when <tt>wxUSE_UNICODE==0</tt>
+    - @c wchar_t when <tt>wxUSE_UNICODE==1</tt> (the default).
+*/
+typedef wxUSE_UNICODE_dependent wxUChar;
+
+/**
+    wxStringCharType is defined to be:
+    - @c char when <tt>wxUSE_UNICODE==0</tt>
+    - @c char when <tt>wxUSE_UNICODE_WCHAR==0</tt> and <tt>wxUSE_UNICODE==1</tt>
+    - @c wchar_t when <tt>wxUSE_UNICODE_WCHAR==1</tt> and <tt>wxUSE_UNICODE==1</tt>
+
+    The @c wxUSE_UNICODE_WCHAR symbol is defined to @c 1 when building on
+    Windows while it's defined to @c 0 when building on Unix, Linux or OS X.
+
+    Note that wxStringCharType is the type used by wxString for internal storage
+    of the characters.
+*/
+typedef wxUSE_UNICODE_WCHAR_dependent wxStringCharType;
+
 //@}