Version: 3.1.6
Runtime Type Information (RTTI)

Detailed Description

wxWidgets uses its own RTTI ("run-time type identification") system which predates the current standard C++ RTTI and so is kept for backwards compatibility reasons but also because it allows some things which the standard RTTI doesn't directly support (such as creating a class from its name).

The standard C++ RTTI can be used in the user code without any problems and in general you shouldn't need to use the functions and the macros in this section unless you are thinking of modifying or adding any wxWidgets classes.

Related Overviews: Runtime Type Information (RTTI)

Related class group: Runtime Type Information (RTTI)

Macros

#define wxDECLARE_APP(className)
 This is used in headers to create a forward declaration of the wxGetApp() function implemented by wxIMPLEMENT_APP(). More...
 
#define wxIMPLEMENT_APP(className)
 This macro defines the application entry point and tells wxWidgets which application class should be used. More...
 
#define wxIMPLEMENT_WXWIN_MAIN
 This macro defines the application entry point appropriate for the current platform. More...
 
#define wxCLASSINFO(className)
 Returns a pointer to the wxClassInfo object associated with this class. More...
 
#define wxDECLARE_ABSTRACT_CLASS(className)
 Used inside a class declaration to declare that the class should be made known to the class hierarchy, but objects of this class cannot be created dynamically. More...
 
#define wxDECLARE_DYNAMIC_CLASS(className)
 Used inside a class declaration to make the class known to wxWidgets RTTI system and also declare that the objects of this class should be dynamically creatable from run-time type information. More...
 
#define wxDECLARE_CLASS(className)
 Used inside a class declaration to declare that the class should be made known to the class hierarchy, but objects of this class cannot be created dynamically. More...
 
#define wxIMPLEMENT_ABSTRACT_CLASS(className, baseClassName)
 Used in a C++ implementation file to complete the declaration of a class that has run-time type information. More...
 
#define wxIMPLEMENT_ABSTRACT_CLASS2(className, baseClassName1, baseClassName2)
 Used in a C++ implementation file to complete the declaration of a class that has run-time type information and two base classes. More...
 
#define wxIMPLEMENT_DYNAMIC_CLASS(className, baseClassName)
 Used in a C++ implementation file to complete the declaration of a class that has run-time type information, and whose instances can be created dynamically. More...
 
#define wxIMPLEMENT_DYNAMIC_CLASS2(className, baseClassName1, baseClassName2)
 Used in a C++ implementation file to complete the declaration of a class that has run-time type information, and whose instances can be created dynamically. More...
 
#define wxIMPLEMENT_CLASS(className, baseClassName)
 Synonym for wxIMPLEMENT_ABSTRACT_CLASS(). More...
 
#define wxIMPLEMENT_CLASS2(className, baseClassName1, baseClassName2)
 Synonym for wxIMPLEMENT_ABSTRACT_CLASS2(). More...
 
#define wx_truncate_cast(T, x)
 This case doesn’t correspond to any standard cast but exists solely to make casts which possibly result in a truncation of an integer value more readable. More...
 
#define wxConstCast(ptr, classname)
 This macro expands into const_cast<classname *>(ptr) if the compiler supports const_cast or into an old, C-style cast, otherwise. More...
 
#define wxDynamicCast(ptr, classname)
 This macro returns the pointer ptr cast to the type classname * if the pointer is of this type (the check is done during the run-time) or NULL otherwise. More...
 
#define wxDynamicCastThis(classname)
 This macro is equivalent to wxDynamicCast(this, classname) but the latter provokes spurious compilation warnings from some compilers (because it tests whether this pointer is non-NULL which is always true), so this macro should be used to avoid them. More...
 
#define wxStaticCast(ptr, classname)
 This macro checks that the cast is valid in debug mode (an assert failure will result if wxDynamicCast(ptr, classname) == NULL) and then returns the result of executing an equivalent of static_cast<classname *>(ptr). More...
 
#define wxGetVariantCast(var, classname)
 This macro returns a pointer to the data stored in var (wxVariant) cast to the type classname if the data is of this type (the check is done during the run-time) or NULL otherwise. More...
 

Functions

wxObjectwxCreateDynamicObject (const wxString &className)
 Creates and returns an object of the given class, if the class has been registered with the dynamic class system using DECLARE... More...
 

Macro Definition Documentation

#define wx_truncate_cast (   T,
 
)

This case doesn’t correspond to any standard cast but exists solely to make casts which possibly result in a truncation of an integer value more readable.

Include file:

#include <wx/defs.h> 
#define wxCLASSINFO (   className)

Returns a pointer to the wxClassInfo object associated with this class.

Include file:

#include <wx/object.h> 
#define wxConstCast (   ptr,
  classname 
)

This macro expands into const_cast<classname *>(ptr) if the compiler supports const_cast or into an old, C-style cast, otherwise.

Include file:

#include <wx/defs.h> 
See also
wxDynamicCast(), wxStaticCast()
#define wxDECLARE_ABSTRACT_CLASS (   className)

Used inside a class declaration to declare that the class should be made known to the class hierarchy, but objects of this class cannot be created dynamically.

Include file:

#include <wx/object.h> 

Example:

1 class wxCommand: public wxObject
2 {
3  wxDECLARE_ABSTRACT_CLASS(wxCommand);
4 
5 private:
6  ...
7 public:
8  ...
9 };
#define wxDECLARE_APP (   className)

This is used in headers to create a forward declaration of the wxGetApp() function implemented by wxIMPLEMENT_APP().

It creates the declaration className& wxGetApp() (requires a final semicolon).

Include file:

#include <wx/app.h> 

Example:

1 wxDECLARE_APP(MyApp);
#define wxDECLARE_CLASS (   className)

Used inside a class declaration to declare that the class should be made known to the class hierarchy, but objects of this class cannot be created dynamically.

The same as wxDECLARE_ABSTRACT_CLASS().

Include file:

#include <wx/object.h> 
#define wxDECLARE_DYNAMIC_CLASS (   className)

Used inside a class declaration to make the class known to wxWidgets RTTI system and also declare that the objects of this class should be dynamically creatable from run-time type information.

Notice that this implies that the class should have a default constructor, if this is not the case consider using wxDECLARE_ABSTRACT_CLASS().

Include file:

#include <wx/object.h> 

Example:

1 class wxFrame: public wxWindow
2 {
3  wxDECLARE_DYNAMIC_CLASS(wxFrame);
4 
5 private:
6  const wxString& frameTitle;
7 public:
8  ...
9 };
#define wxDynamicCast (   ptr,
  classname 
)

This macro returns the pointer ptr cast to the type classname * if the pointer is of this type (the check is done during the run-time) or NULL otherwise.

Usage of this macro is preferred over obsoleted wxObject::IsKindOf() function.

The ptr argument may be NULL, in which case NULL will be returned.

Include file:

#include <wx/object.h> 

Example:

1 wxWindow *win = wxWindow::FindFocus();
2 wxTextCtrl *text = wxDynamicCast(win, wxTextCtrl);
3 if ( text )
4 {
5  // a text control has the focus...
6 }
7 else
8 {
9  // no window has the focus or it is not a text control
10 }
See also
Runtime Type Information (RTTI), wxDynamicCastThis(), wxConstCast(), wxStaticCast()
#define wxDynamicCastThis (   classname)

This macro is equivalent to wxDynamicCast(this, classname) but the latter provokes spurious compilation warnings from some compilers (because it tests whether this pointer is non-NULL which is always true), so this macro should be used to avoid them.

Include file:

#include <wx/object.h> 
See also
wxDynamicCast()
#define wxGetVariantCast (   var,
  classname 
)

This macro returns a pointer to the data stored in var (wxVariant) cast to the type classname if the data is of this type (the check is done during the run-time) or NULL otherwise.

Include file:

#include <wx/variant.h> 
See also
Runtime Type Information (RTTI), wxDynamicCast()
#define wxIMPLEMENT_ABSTRACT_CLASS (   className,
  baseClassName 
)

Used in a C++ implementation file to complete the declaration of a class that has run-time type information.

Include file:

#include <wx/object.h> 

Example:

1 wxIMPLEMENT_ABSTRACT_CLASS(wxCommand, wxObject);
2 
3 wxCommand::wxCommand()
4 {
5  ...
6 }
#define wxIMPLEMENT_ABSTRACT_CLASS2 (   className,
  baseClassName1,
  baseClassName2 
)

Used in a C++ implementation file to complete the declaration of a class that has run-time type information and two base classes.

Include file:

#include <wx/object.h> 
#define wxIMPLEMENT_APP (   className)

This macro defines the application entry point and tells wxWidgets which application class should be used.

The two tasks performed by this macro can be done separately by using wxIMPLEMENT_APP_NO_MAIN() and wxIMPLEMENT_WXWIN_MAIN() macros, but in a typical GUI application it's simpler and more convenient to use this macro to do both together.

The className passed to this macro must be a name of the class deriving from wxApp.

Note that this macro requires a final semicolon.

Include file:

#include <wx/app.h> 

Example:

1 wxIMPLEMENT_APP(MyApp);
See also
wxDECLARE_APP()
#define wxIMPLEMENT_CLASS (   className,
  baseClassName 
)

Synonym for wxIMPLEMENT_ABSTRACT_CLASS().

Please prefer to use the more clear, if longer, wxIMPLEMENT_ABSTRACT_CLASS in the new code.

Include file:

#include <wx/object.h> 
#define wxIMPLEMENT_CLASS2 (   className,
  baseClassName1,
  baseClassName2 
)

Synonym for wxIMPLEMENT_ABSTRACT_CLASS2().

Please prefer to use the more clear, if longer, wxIMPLEMENT_ABSTRACT_CLASS2 in the new code.

Include file:

#include <wx/object.h> 
#define wxIMPLEMENT_DYNAMIC_CLASS (   className,
  baseClassName 
)

Used in a C++ implementation file to complete the declaration of a class that has run-time type information, and whose instances can be created dynamically.

Include file:

#include <wx/object.h> 

Example:

1 wxIMPLEMENT_DYNAMIC_CLASS(wxFrame, wxWindow);
2 
3 wxFrame::wxFrame()
4 {
5  ...
6 }
#define wxIMPLEMENT_DYNAMIC_CLASS2 (   className,
  baseClassName1,
  baseClassName2 
)

Used in a C++ implementation file to complete the declaration of a class that has run-time type information, and whose instances can be created dynamically.

Use this for classes derived from two base classes.

Include file:

#include <wx/object.h> 
#define wxIMPLEMENT_WXWIN_MAIN

This macro defines the application entry point appropriate for the current platform.

Note that usually wxIMPLEMENT_APP() is used instead of this macro.

For most platforms, it defines main() function, but for GUI Windows applications, it defines WinMain() instead.

In either case, the macro expansion includes the call to wxDISABLE_DEBUG_SUPPORT() which disables debugging code in release builds. If you don't use this macro, but define the entry point yourself, you probably want to call wxDISABLE_DEBUG_SUPPORT() explicitly.

Include file:

#include <wx/app.h> 
#define wxStaticCast (   ptr,
  classname 
)

This macro checks that the cast is valid in debug mode (an assert failure will result if wxDynamicCast(ptr, classname) == NULL) and then returns the result of executing an equivalent of static_cast<classname *>(ptr).

Include file:

#include <wx/object.h> 
See also
wxDynamicCast(), wxConstCast()

Function Documentation

wxObject* wxCreateDynamicObject ( const wxString className)

Creates and returns an object of the given class, if the class has been registered with the dynamic class system using DECLARE...

and IMPLEMENT... macros.

Include file:

#include <wx/object.h>