// Purpose: topic overview
// Author: wxWidgets team
// RCS-ID: $Id$
-// Licence: wxWindows license
+// Licence: wxWindows licence
/////////////////////////////////////////////////////////////////////////////
/**
@page overview_container Container Classes
-Classes: wxList<T>, wxArray<T>, wxVector<T>
+Classes: wxList<T>, wxArray<T>, wxVector<T>, wxStack<T>, wxHashMap, wxHashSet
-wxWidgets uses itself several container classes including doubly-linked lists
-and dynamic arrays (i.e. arrays which expand automatically when they become
-full). For both historical and portability reasons wxWidgets does not use STL
-which provides the standard implementation of many container classes in C++.
+@section overview_container_intro Overview
-First of all, wxWidgets has existed since well before STL was written, and
-secondly we don't believe that today compilers can deal really well with all of
-STL classes (this is especially true for some less common platforms). Of
-course, the compilers are evolving quite rapidly and hopefully their progress
-will allow to base future versions of wxWidgets on STL - but this is not yet
-the case.
+For historical reasons, wxWidgets uses custom container classes internally.
+This was unfortunately unavoidable during a long time when the standard library
+wasn't widely available and can't be easily changed even now that it is for
+compatibility reasons. If you are building your own version of the library and
+don't care about compatibility nor slight (less than 5%) size penalty imposed
+by the use of STL classes, you may choose to use the "STL" build of wxWidgets
+in which these custom classes are replaced with their standard counterparts and
+only read the section @ref overview_container_std explaining how to do it.
-wxWidgets container classes don't pretend to be as powerful or full as STL
-ones, but they are quite useful and may be compiled with absolutely any C++
-compiler. They're used internally by wxWidgets, but may, of course, be used in
-your programs as well if you wish.
+Otherwise you will need to know about the custom wxWidgets container classes
+such as wxList<T> and wxArray<T> if only to use wxWidgets functions that work
+with them, e.g. wxWindow::GetChildren(), and you should find the information
+about using these classes below useful.
+
+Notice that we recommend that you use standard classes directly in your own
+code instead of the container classes provided by wxWidgets in any case as the
+standard classes are easier to use and may also be safer because of extra
+run-time checks they may perform as well as more efficient.
+
+Finally notice that recent versions of wxWidgets also provide standard-like
+classes such as wxVector<T>, wxStack<T> or wxDList which can be used exactly
+like the std::vector<T>, std::stack<T> and std::list<T*>, respectively, and
+actually are just typedefs for the corresponding types if wxWidgets is compiled
+in STL mode. These classes could be useful if you wish to avoid the use of the
+standard library in your code for some reason.
+
+To summarize, you should use the standard container classes such as
+std::vector<T> and std::list<T> if possible and wxVector<T> or wxDList<T> if
+it isn't and only use legacy wxWidgets containers such as wxArray<T> and
+wxList<T> when you must, i.e. when you use a wxWidgets function taking or
+returning a container of such type.
+
+
+@section overview_container_legacy Legacy Classes
The list classes in wxWidgets are doubly-linked lists which may either own the
objects they contain (meaning that the list deletes the object when it is
own the object pointers to which they store.
For the same portability reasons, the container classes implementation in
-wxWidgets does not use templates, but is rather based on C preprocessor i.e. is
-done with the macros: WX_DECLARE_LIST() and WX_DEFINE_LIST() for the linked
-lists and WX_DECLARE_ARRAY(), WX_DECLARE_OBJARRAY() and WX_DEFINE_OBJARRAY()
-for the dynamic arrays.
+wxWidgets don't use templates, but are rather based on C preprocessor i.e. are
+implemented using the macros: WX_DECLARE_LIST() and WX_DEFINE_LIST() for the
+linked lists and WX_DECLARE_ARRAY(), WX_DECLARE_OBJARRAY() and
+WX_DEFINE_OBJARRAY() for the dynamic arrays.
The "DECLARE" macro declares a new container class containing the elements of
given type and is needed for all three types of container classes: lists,
wxArrayString is somewhat special: it is an optimized version of wxArray which
uses its knowledge about wxString reference counting schema.
+
+@section overview_container_std STL Build
+
+To build wxWidgets with the standard containers you need to set
+wxUSE_STD_CONTAINERS option to 1 in @c wx/msw/setup.h for wxMSW builds or
+specify @c --enable-std_containers option to configure (which is also
+implicitly enabled by @c --enable-stl option) in Unix builds.
+
+The standard container build is mostly, but not quite, compatible with the
+default one. Here are the most important differences:
+ - wxList::compatibility_iterator must be used instead of wxList::Node* when
+ iterating over the list contents. The compatibility_iterator class has the
+ same semantics as a Node pointer but it is an object and not a pointer, so
+ you need to write
+ @code
+ for ( wxWindowList::compatibility_iterator it = list.GetFirst();
+ it;
+ it = it->GetNext() )
+ ...
+ @endcode
+ instead of the old
+ @code
+ for ( wxWindowList::Node *n = list.GetFirst(); n; n = n->GetNext() )
+ ...
+ @endcode
+ - wxSortedArrayString and wxArrayString are separate classes now and the
+ former doesn't derive from the latter. If you need to convert a sorted array
+ to a normal one, you must copy all the elements. Alternatively, you may
+ avoid the use of wxSortedArrayString by using a normal array and calling its
+ Sort() method when needed.
+ - WX_DEFINE_ARRAY_INT(bool) cannot be used because of the differences in
+ std::vector<bool> specialization compared with the generic std::vector<>
+ class. Please either use std::vector<bool> directly or use an integer array
+ instead.
+
+
*/
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