added IsFalse() to simplify code doing HasOption(very-long-option-name) && !GetOptionInt(the-same-very-long-option-name) elsewhere

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@33004 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

docs/latex/wx/sysopt.tex

@@ -125,6 +125,16 @@ Returns \true if the given option is present. The function is case-insensitive t
 \helpref{wxSystemOptions::GetOptionInt}{wxsystemoptionsgetoptionint}
 
 
+\membersection{wxSystemOptions::IsFalse}\label{wxsystemoptionsisfalse}
+
+\constfunc{bool}{IsFalse}{\param{const wxString\&}{ name}}
+
+Returns \true if the option with the given \arg{name} had been set to $0$
+value. This is mostly useful for boolean options for which you can't use
+\texttt{GetOptionInt(name) == 0} as this would also be true if the option
+hadn't been set at all.
+
+
 \membersection{wxSystemOptions::SetOption}\label{wxsystemoptionssetoption}
 
 \func{void}{SetOption}{\param{const wxString\&}{ name}, \param{const wxString\&}{ value}}

include/wx/sysopt.h

@@ -34,6 +34,11 @@ public:
     static wxString GetOption(const wxString& name);
     static int GetOptionInt(const wxString& name);
     static bool HasOption(const wxString& name);
+
+    static bool IsFalse(const wxString& name)
+    {
+        return HasOption(name) && GetOptionInt(name) == 0;
+    }
 };
 
 #if !wxUSE_SYSTEM_OPTIONS