// Purpose: topic overview
// Author: wxWidgets team
// RCS-ID: $Id$
-// Licence: wxWindows license
+// Licence: wxWindows licence
/////////////////////////////////////////////////////////////////////////////
-/*!
-
- @page overview_container Container classes overview
-
- Classes: #wxListT, #wxArrayT, #wxVectorT
-
- 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++.
-
- 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.
-
- 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.
-
- 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
- removed from the list or the list itself is destroyed) or just store the
- pointers depending on whether you called or not wxList::DeleteContents method.
-
- Dynamic arrays resemble C arrays but with two important differences: they
- provide run-time range checking in debug builds and they automatically expand
- the allocated memory when there is no more space for new items. They come in
- two sorts: the "plain" arrays which store either built-in types such as "char",
- "int" or "bool" or the pointers to arbitrary objects, or "object arrays" which
- 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: @e WX_DECLARE_LIST and @e WX_DEFINE_LIST for the linked
- lists and @e WX_DECLARE_ARRAY, @e WX_DECLARE_OBJARRAY and @e 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,
- arrays and objarrays. The "DEFINE" classes must be inserted in your program
- in a place where the @b full declaration of container element class is in scope
- (i.e. not just forward declaration), otherwise destructors of the container
- elements will not be called!
-
- As array classes never delete the items they contain anyhow, there is
- no WX_DEFINE_ARRAY macro for them.
-
- Examples of usage of these macros may be found in #wxList and #wxArray documentation.
-
- Finally, wxWidgets predefines several commonly used container classes. wxList
- is defined for compatibility with previous versions as a list containing
- wxObjects and wxStringList as a list of C-style strings (char *), both of these
- classes are deprecated and should not be used in new programs. The following
- array classes are defined: wxArrayInt, wxArrayLong, wxArrayPtrVoid and
- wxArrayString. The first three store elements of corresponding types, but
- wxArrayString is somewhat special: it is an optimized version of wxArray which
- uses its knowledge about #wxString reference counting schema.
+/**
+
+@page overview_container Container Classes
+
+@tableofcontents
+
+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.
+
+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.
+
+@see @ref group_class_containers
+
+
+
+@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
+removed from the list or the list itself is destroyed) or just store the
+pointers depending on whether or not you called wxList<T>::DeleteContents()
+method.
+
+Dynamic arrays resemble C arrays but with two important differences: they
+provide run-time range checking in debug builds and they automatically expand
+the allocated memory when there is no more space for new items. They come in
+two sorts: the "plain" arrays which store either built-in types such as "char",
+"int" or "bool" or the pointers to arbitrary objects, or "object arrays" which
+own the object pointers to which they store.
+
+For the same portability reasons, the container classes implementation in
+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,
+arrays and objarrays. The "DEFINE" classes must be inserted in your program in
+a place where the @e full declaration of container element class is in scope
+(i.e. not just forward declaration), otherwise destructors of the container
+elements will not be called!
+
+As array classes never delete the items they contain anyhow, there is no
+WX_DEFINE_ARRAY() macro for them.
+
+Examples of usage of these macros may be found in wxList<T> and wxArray<T>
+documentation.
+
+Finally, wxWidgets predefines several commonly used container classes. wxList
+is defined for compatibility with previous versions as a list containing
+wxObjects and wxStringList as a list of C-style strings (char *), both of these
+classes are deprecated and should not be used in new programs. The following
+array classes are defined: wxArrayInt, wxArrayLong, wxArrayPtrVoid and
+wxArrayString. The first three store elements of corresponding types, but
+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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