path: root/docs/gtk.texi

\input texinfo @c -*-texinfo-*-
@c Copyright (C) 1996 by Peter Mattis. All rights reserved.
@c
@c %**start of header
@setfilename gtk.info
@settitle GTK
@setchapternewpage odd
@include macros.texi
@c %**end of header

@set edition 1.0
@set update-date 9 April 1997
@set update-month April 1997

@ifinfo
This file documents GTK, the General Toolkit

Copyright (C) 1996 Peter Mattis
Copyright (C) 1997 Peter Mattis

Permission is granted to make and distribute verbatim copies of this
manual provided the copyright notice and this permission notice are
preserved on all copies

@ignore
Permission is granted to process this file throught TeX and print the
results, provided the printed document carries copying permission notice
identical to this one except for the removal of this paragraph (this
paragraph not being relevant to the printed manual).

@end ignore
Permission is granted to copy and distribute modified versions of this
manual under the conditions for verbatim copying, provided that the
entire resulting derived work is distributed under the terms of a
permission notice identical to this one.

Permission is granted to copy and distribute translations of this manual
into another language, under the above conditions for modified versions,
except that this permission notice may be stated in a translation
approved by Peter Mattis.
@end ifinfo

@titlepage
@title The General Toolkit
@subtitle Version @value{edition}
@subtitle @value{update-month}
@author by Peter Mattis

@page
@vskip 0pt plus 1filll
Copyright @copyright{} 1996 Peter Mattis
Copyright @copyright{} 1997 Peter Mattis

Permission is granted to make and distribute verbatim copies of this
manual provided the copyright notice and this permission notice are
preserved on all copies.

Permission is granted to copy and distribute modified versions of this
manual under the conditions for verbatim copying, provided that the
entire resulting derived work is distributed under the terms of a
permission notice identical to this one.

Permission is granted to copy and distribute translations of this manual
into another language, under the above conditions for modified versions,
except that this permission notice may be stated in a translation
approved by Peter Mattis.
@end titlepage

@dircategory User Interface Toolkit
@direntry
* GTK: (gtk).		The General Toolkit
@end direntry

@node Top, Copying, (dir), (dir)
@top The General Toolkit
@ifinfo
This is edition @value{edition} of the GTK documentation,
@w{@value{update-date}}.
@end ifinfo

@menu
* Copying::                     Your rights.
* Overview::                    What is GTK?
* Objects::                     Object overview.
* Signals::                     Signals overview.
* Widgets::                     Widget overview.
* Other Objects::               Utility objects.
* Miscellaneous::               Initialization, exit and other features.
* Examples::                    Using GTK.
* Object Implementation::       Object internals.
* Signal Implementation::       Signal internals.
* Widget Implementation::       Widget internals.
* Function Index::              Index of functions.
* Concept Index::               Index of concepts.
@end menu

@node Copying, Overview, Top, Top
@comment node-name, next, previous, up
@chapter Copying

GTK is @dfn{free}; this means that everyone is free to use it and free
to redestribute it on a free basis. GTK is not in the public domain; it
is copyrighted and there are restrictions on its distribution, but
these restrictions are designed to permit everything that a good
cooperating citizen would want to do. What is not allowed is to try to
prevent others from further sharing any version of GTK that they might
get from you.

Specifically, we want to make sure that you have the right to give away
copies of GTK, that you receive source code or else can get it if you
want it, that you can change GTK or use pieces of it in new free
programs, and that you know you can do these things.

To make sure that everyone has such rights, we have to forbid you to
deprive anyone else of these rights. For example, if you distribute
copies of GTK, you must give the recipients all the rights that you
have. You must make sure that they, too, receive or can get the source
code. And you must tell them their rights.

Also, for my own protection, we must make certain that everyone finds
out that there is no warranty for GTK. If GTK is modified by someone
else and passed on, we want their recipients to know that what they have
is not what we distributed, so that any problems introduced by others
will no reflect on our reputation.

The precise conditions of the licenses for GTK are found in the General
Public Licenses that accompanies it.


@node Overview, Objects, Copying, Top
@comment node-name, next, previous, up
@chapter What is GTK?
@cindex Overview

GTK is a library for creating graphical user interfaces similar to the
Motif ``look and feel''. It is designed to be small and efficient, but
still flexible enough to allow the programmer freedom in the interfaces
created. GTK allows the programmer to use a variety of standard user
interface widgets (@pxref{Widgets}) such as push, radio and check
buttons, menus, lists and frames. It also provides several ``container''
widgets which can be used to control the layout of the user interface
elements.

GTK provides some unique features. (At least, I know of no other widget
library which provides them). For example, a button does not contain a
label, it contains a child widget, which in most instances will be a
label. However, the child widget can also be a pixmap, image or any
combination possible the programmer desires. This flexibility is adhered
to throughout the library.


@node Objects, Signals, Overview, Top
@comment node-name, next, previous, up
@chapter Object Overview
@cindex Objects

GTK implements a semi-simple class mechanism and an associated class
hierarchy for widgets and several other useful objects. The GtkObject
type is the root of the class hierarchy. It provides a few items needed
by all classes, the foundation for the signal (@pxref{Signals})
mechanism and the ``destroy'' method.

The class hierarchy is defined by a type hierarchy. This hierarchy
allows queries to be made in regards to a type. The basic query that can
be performed is asking whether a given type has an ``is a'' relation
with another type. For instance, it is common to ask whether a general
widget pointer is a type of specific widget so that runtime sanity
checks can be made.

@section Type utility functions

The @code{GtkTypeInfo} structure is used to communicate information to
@code{gtk_type_unique} as opposed to passing in large numbers of
parameters.

@example
typedef struct _GtkTypeInfo GtkTypeInfo;

struct _GtkTypeInfo
@{
  gchar *type_name;
  guint object_size;
  guint class_size;
  GtkClassInitFunc class_init_func;
  GtkObjectInitFunc object_init_func;
  GtkValueInitFunc value_init_func;
@}
@end example

@itemize @bullet
@item
The @code{type_name} field refers to the name of the type. It is
convention for the type name to be the same as the C structure type. For
example, the type name of the @code{GtkObject} structure is
``GtkObject''.

@item
The @code{object_size} field refers to the size in bytes of the C
structure. The easiest (and portable) means of computing this size is by
using the C @code{sizeof} operator. For instance, the sizeof of the
@code{GtkObject} structure is computed by doing @code{sizeof
(GtkObject)}.

@item
The @code{class_size} field refers to the size in bytes of the C
structure for the class. Again, the @code{sizeof} operator should be
used to compute this value.

@item
The @code{class_init_func} field is a callback which is used by the type
mechanism to initialize class specific fields. The single argument this
function takes is a pointer to a class structure.

@item
The @code{object_init_func} field is a callback which is used by the
type mechanism to initialize object specific fields. The single argument
this functions takes is a pointer to an object structure.

@item
The @code{value_init_func} field is a callback which is used by the type
mechanism to initialize object stack value types. (FIXME: unfinished).
@end itemize

@deftypefun guint gtk_type_unique (guint @var{parent_type}, GtkTypeInfo *@var{type_info})
The @var{parent_type} is simply the value of the new types parent
type. If @var{parent_type} is 0, then the new type is the root of the
type hierarchy. @var{type_info} is a pointer to a structure which
contains necessary information for construction of the new
type. Specifically, the @code{type_name}, @code{object_size} and
@code{class_size} fields are required. The @code{class_init_func},
@code{object_init_func} and @code{value_init_func} fields may be NULL.
@end deftypefun

@deftypefun gchar* gtk_type_name (guint @var{type})
The returned string is the name of @var{type} as specified to
@code{gtk_type_unique}.
@end deftypefun

@deftypefun guint gtk_type_from_name (guchar *@var{name})
Return the type associated with @var{name}. If there is no type
associated with @var{name}, then 0 will be returned.
@end deftypefun

@deftypefun guint gtk_type_parent (guint @var{type})
Returns the parent type of @var{type} or 0 if @var{type} is the root of
the type hierarchy.
@end deftypefun

@deftypefun gpointer gtk_type_class (guint @var{type})
Returns the initialized class structure for @var{type}. The class
structure is actually created and initialized the first time it is
needed. If creation and initialization occurs, the @code{class_size}
field of the @code{GtkTypeInfo} structure used to initialize this type
is used to determine how large the class structure is. The
@code{class_init_func} field from the @code{GtkTypeInfo} structure is
called for all the members in the types ancestry, including the
type. The order of this invocation proceeds from the root on down. For
example, the @code{GtkWidgetClass} is first initialized as an
@code{GtkObjectClass} by the object class initialization routine and
then by the widget class initialization routine. This allows the widget
class initialization routine to override values set by the object class
initialization routine. The returned structure is shared by all objects
of @var{type} and, as such, should not be modified.
@end deftypefun

@deftypefun gpointer gtk_type_new (guint @var{type})
Returns a new instance of an @var{type} object. The object structure is
created and initialized similarly to the class structure (as described
above). The @code{object_size} and @code{object_init_func} fields of the
@code{GtkTypeInfo} structure are used to determine the objects allocated
size and the object specific initialization routine. Similarly to the
class initialization, all the object initialization routines from the
root on down to the particular type being created are invoked.
@end deftypefun

@deftypefun void gtk_type_describe_heritage (guint @var{type})
Prints the type heritage for @var{type}. The heritage for a type
includes the type and all its parent types up the type tree.
@end deftypefun

@deftypefun void gtk_type_describe_tree (guint @var{type}, gint @var{show_size})
Prints the type tree which starts at @var{type}. @var{show_size} is a
boolean which determines whether type sizes are printed.
@end deftypefun

@deftypefun gint gtk_type_is_a (guint @var{type}, guint @var{is_a_type})
A predicate function which determines whether the relation @var{type}
is_a @var{is_a_type} is true.
@end deftypefun

@section Object functions

The GtkObject type is the root of the type hierarchy used by GTK. It
provides a minimal set of fields used to implement the actual
object, class and signal mechanisms, as well as several utility routines
which make dealing with objects easier.

For the adventurous, see @ref{Object Implementation}.

@deftypefun guint gtk_object_get_type (void)
Returns the @code{GtkObject} type identifier.
@end deftypefun

@deftypefun void gtk_object_class_add_signals (GtkObjectClass *@var{class}, gint *@var{signals}, gint @var{nsignals})
Adds @var{signals} to the @code{signals} field in the GtkObjectClass
structure @var{class}. @xref{Signals}.
@end deftypefun

@deftypefun void gtk_object_destroy (GtkObject *@var{object})
Performs checks to make sure it is alright to destroy @var{object} and
then emits the @code{destroy} signal. The check which is performed is to
make sure @var{object} is not already processing another signal. If this
were the case then destroying the object immediately would undoubtedly
cause problems as the other signal would not be able to tell the object
was destroyed. The solution is that if @var{object} is processing another
signal we mark @var{object} is needing to be destroyed. When we finish
processing of the other signal we check whether the object needs to be
destroyed.
@end deftypefun

The GtkObject type provides a mechanism for associating arbitrary
amounts of data with an object. The data is associated with the object
using a character string key. The functions @code{gtk_object_set_data},
@code{gtk_object_get_data}, and @code{gtk_object_remove_data} are the
interface to this mechanism. Two other routines,
@code{gtk_object_set_user_data} and @code{gtk_object_get_user_data},
exist as convenience functions which simply use the same mechanism.

@deftypefun void gtk_object_set_data (GtkObject *@var{object}, const char *@var{key}, gpointer @var{data})
Associate @var{data} with @var{key} in the data list of @var{object}.
@end deftypefun

@deftypefun gpointer gtk_object_get_data (GtkObject *@var{object}, const char *@var{key})
Retrieve the data associated with @var{key} in the data list of @var{object}.
@end deftypefun

@deftypefun void gtk_object_remove_data (GtkObject *@var{object}, const char *@var{key})
Remove the data associated with @var{key} in the data list of @var{object}.
@end deftypefun

@deftypefun void gtk_object_set_user_data (GtkObject *@var{object}, gpointer @var{data})
Sets @var{data} into the @code{user_data} field of @var{object}.
@end deftypefun

@deftypefun gpointer gtk_object_get_user_data (GtkObject *@var{object})
Returns the @code{user_data} field of @var{object}.
@end deftypefun

The GtkObject type also provides a mechanism for specifying
initialization values for fields. This general mechanism is called
object value stacks. The reason for using value stacks is that they can
simplify the life of the programmer. For instance, by default widgets
are non-visible when created. However, the ``visible'' value for widgets
may be specified so that widgets are made visible when created. (FIXME:
unfinished).

@deftypefun void gtk_object_value_stack_new (guint @var{object_type}, const gchar *@var{value_id}, GtkParamType @var{value_type})
@end deftypefun

@deftypefun void gtk_object_push_value (guint @var{object_type}, const gchar *@var{value_id}, @dots{})
Push a value on the value stack specified by @var{object_type} and
@var{value_id}. The type of value is implicitly given in the context of
@var{object_type} and @var{value_id}. (That is, it is not specified
explicitly in the function call). Only a single extra argument is
expected which is the data which is to be placed on the stack.
@end deftypefun

@deftypefun void gtk_object_pop_value (guint @var{object_type}, const gchar *@var{value_id})
Pop a value of the value stack specified by @var{object_type} and
@var{value_id}.
@end deftypefun

@deftypefun gint gtk_object_peek_value (guint @var{object_type}, const gchar *@var{value_id}, gpointer @var{data})
Peek at the value on the top of the value stack specified by
@var{object_type} and @var{value_id}. The @var{data} argument is
interpreted as the location of where to place the ``peeked'' data. For
instance, if the peeked data is of type @code{GTK_PARAM_POINTER}, then
@var{data} will be a pointer to a pointer. If the value stack is empty
or does not exist or an error occurs, @code{gtk_object_peek_value} will
return @code{FALSE}. On success it will return @code{TRUE}.
@end deftypefun


@node Signals, Widgets, Objects, Top
@comment node-name, next, previous, up
@chapter Signals Overview
@cindex Signals

Signals are GTK's method for objects to perform callbacks. A signal is
an event which occurs upon an object. The programmer can connect to a
signal of an object which involves specifying a function to be called
when that signal is emitted in the specified object.

When a signal is emitted, both the class function associated with the
signal (when it was defined) and all signal handlers installed for that
signal on the particular object emitting the signal are called. The
widget programmer can specify whether the class function is to be called
before after or both before and after the signal handlers installed by
the widget user. The widget user can, however, specify that their signal
handler is to be run after the class function (using the ``_after''
signal connection routines). Any signal handling function can emit the
same signal on the same object while it is running causing that signal
emittion to either restart or to run recursively. Additionally, signal
emittion can be terminated prematurely. While both such abilities are
rarely used, they do allow for greater flexibility in regards to
signals. For instance, a programmer can attach to the key press event
signal and intercept all tab key presses from a widget. This particular
example is used in the file selection dialog to implement tab completion
of filenames and prevent the entry widget from inserting the tab into
its buffer.

Signals are selected using either an integer identifier or a character
string name. It is convention to name the signal the same as the class
function which is associated with it. There are two versions of most of
the signal functions, one which takes an integer identifier and one
which takes a character string name for the signal.

@deftypefun gint gtk_signal_new (gchar *@var{name}, GtkSignalRunType @var{run_type}, gint @var{object_type}, gint @var{function_offset}, GtkSignalMarsahller @var{marshaller}, GtkParamType @var{return_val}, gint @var{nparams}, @dots{})
Create a new signal and give it the character string identifier
@var{name}. @var{name} needs to be unique in the context of
@var{object_type}'s branch of the class hierarchy. That is,
@var{object_type} cannot create a signal type with the same name as a
signal type created by one of its parent types.

@var{run_type} specifies whether the class function should be run before
(@code{GTK_RUN_FIRST}), after (@code{GTK_RUN_LAST}) or both before and
after normal signal handlers (@code{GTK_RUN_BOTH}). Additionally, the
@code{GTK_RUN_NO_RECURSE} value can be or'ed with any of those values to
specify that the signal should not be recursive. By default, emitting
the same signal on the same widget will cause the signal to be emitted
twice. However, if the @code{GTK_RUN_NO_RECURSE} flag is specified,
emitting the same signal on the same widget will cause the current
signal emittion to be restarted. This allows the widget programmer to
specify the semantics of signal emittion on a per signal
basis. (The @code{GTK_RUN_NO_RECURSE} flag is used by the GtkAdjustment
widget).

The @var{function_offset} is the byte offset from the start of the class
structure to the class function field within the class structure. The
easiest means to compute this offset is by using the
@code{GTK_SIGNAL_OFFSET} macro which takes the class structure type as
the first argument and the field as the second argument. For example,
@code{GTK_SIGNAL_OFFSET (GtkObjectClass, destroy)} will give the offset
of the @code{destroy} class function within the
@code{GtkObjectClass}. Note: An offset is specified instead of an
absolute location since there will be multiple instances of a class
structure being referenced. (The @code{GtkWidgetClass} structure ``is
a'' @code{GtkObjectClass} structure, etc.)

The @var{marshaller} function is used to invoke a signal handler. Since
signal handlers may take different parameters and return values and a
general mechanism for invoking them is not apparent, the approach of
making the signal creator responsible for invoking the signal handler
was taken. (FIXME: unfinished).

The @var{return_val} and @var{nparams} and the remaining arguments
specify the return value and the arguments to the signal handler
respectively. Note: There is an implicit first argument to every signal
handler which is the widget the signal has been emitted from. The
variable argument list (@var{@dots{}}) specifies the types of the
arguments. These can be one of @code{GTK_PARAM_CHAR},
@code{GTK_PARAM_SHORT}, @code{GTK_PARAM_INT}, @code{GTK_PARAM_LONG},
@code{GTK_PARAM_POINTER} or @code{GTK_PARAM_FUNCTION}. It is undefined
to specify @code{GTK_PARAM_NONE} as an argument type, however it is ok
to use @code{GTK_PARAM_NONE} for @var{return_val}. (This corresponds to
returning a @code{void}).

@code{gtk_signal_new} returns the integer identifier of the newly
created signal. Signal identifiers start numbering at 1 and increase
upwards. A value of -1 will be returned if an error occurs.

@strong{Note:} @code{gtk_signal_new} is only needed by widget writers. A
normal user of GTK will never needed to invoke this function.
@end deftypefun

@deftypefun gint gtk_signal_lookup (gchar *@var{name}, gint @var{object_type})
Returns the integer identifier for the signal referenced by @var{name}
and @var{object_type}. If @var{object_type} does not define the signal
@var{name}, then the signal is looked for in @var{object_type}'s parent
type recursively.
@end deftypefun

@deftypefun gint gtk_signal_emit (GtkObject *@var{object}, gint @var{signal_type}, @dots{})
Emit the signal specified by the integer identifier @var{signal_type}
from @var{object}. If an error occurs, @code{gtk_signal_emit} will
return @code{FALSE} and will return @code{TRUE} on success. The signal
definition determines the parameters passed in the variable argument
list (@code{@dots{}}). For example, if the signal is defined as:

@example
  gint (* event) (GtkWidget *widget, GdkEvent *event);
@end example

Then a call to emit the ``event'' signal would look like:

@example
  GdkEvent event;
  gint return_val;
  @dots{}
  gtk_signal_emit (some_object,
                   gtk_signal_lookup ("event",
                     GTK_OBJECT_TYPE (some_object)),
                   &event, &return_val);
@end example

Notice that the @code{widget} argument is implicit in that the first
argument to every signal is a type derived from @code{GtkObject}. The
@var{return_val} argument is actually a pointer to the return value type
since the signal mechanism needs to be able to place the return value in
an actual location. And lastly, the @code{gtk_signal_lookup} call is
normally avoided by using the @code{gtk_signal_emit_by_name} function
instead. @code{gtk_signal_emit} is normally used internally by widgets
which know the signal identifier (since they defined the signal) and can
therefore side-step the cost of calling @code{gtk_signal_lookup}.
@end deftypefun

@deftypefun gint gtk_signal_emit_by_name (GtkObject *@var{object}, gchar *@var{name}, @dots{})
Similar to @code{gtk_signal_emit} except that the signal is referenced
by @var{name} instead of by its integer identifier.
@end deftypefun

@deftypefun void gtk_signal_emit_stop (GtkObject *@var{object}, gint @var{signal_type})
Stop the emission of the signal @var{signal_type} on
@var{object}. @var{signal_type} is the integer identifier for the signal
and can be determined using the function
@code{gtk_signal_lookup}. Alternatively, the function
@code{gtk_signal_emit_stop_by_name} can be used to refer to the signal
by name. Attempting to stop the emission of a signal that isn't being
emitted does nothing.
@end deftypefun

@deftypefun void gtk_signal_emit_stop_by_name (GtkObject *@var{object}, gchar *@var{name})
Similar to @code{gtk_signal_emit_stop} except that the signal is
referenced by @var{name} instead of by its integer identifier.
@end deftypefun

@deftypefun gint gtk_signal_connect (GtkObject *@var{object}, gchar *@var{name}, GtkSignalFunc @var{func}, gpointer @var{func_data})
Connects a signal handling function to a signal emitting
object. @var{func} is connected to the signal @var{name} emitted by
@var{object}. The arguments and returns type of @var{func} should match
the arguments and return type of the signal @var{name}. However,
@var{func} may take the extra argument of @var{func_data}. Due to the C
calling convention it is ok to ignore the extra argument. (It is ok to
ignore all the arguments in fact).

@code{gtk_signal_connect} returns an integer identifier for the
connection which can be used to refer to it in the future. Specifically
it is useful for removing the connection and/or blocking it from being
used.
@end deftypefun

@deftypefun gint gtk_signal_connect_after (GtkObject *@var{object}, gchar *@var{name}, GtkSignalFunc @var{func}, gpointer @var{func_data})
Similar to @code{gtk_signal_connect} except the signal handler is
connected in the ``after'' slot. This allows a signal handler to be
guaranteed to run after other signal handlers connected to the same
signal on the same object and after the class function associated with
the signal.

Like @code{gtk_signal_connect}, @code{gtk_signal_connect_after} returns
an integer identifier which can be used to refer to the connection.
@end deftypefun

@deftypefun gint gtk_signal_connect_object (GtkObject *@var{object}, gchar *@var{name}, GtkSignalFunc @var{func}, GtkObject *@var{slot_object})
Connects @var{func} to the signal @var{name} emitted by
@var{object}. Similar to @code{gtk_signal_connect} with the difference
that @var{slot_object} is passed as the first parameter to @var{func}
instead of the signal emitting object. This can be useful for connecting
a signal emitted by one object to a signal in another object. A common
usage is to connect the ``destroy'' signal of dialog to the ``clicked''
signal emitted by a ``close'' button in the dialog. That is, the
``clicked'' signal emitted by the button will caused the ``destroy''
signal to be emitted for the dialog. This is also the ``right'' way to
handle closing of a dialog since the ``destroy'' signal will be sent if
the dialog is deleted using a window manager function and this enables
the two methods of closing the window to be handled by the same
mechanism. Returns an integer identifier which can be used to refer to
the connection.
@end deftypefun

@deftypefun gint gtk_signal_connect_object_after (GtkObject *@var{object}, gchar *@var{name}, GtkSignalFunc @var{func}, GtkObject *@var{slot_object})
Similar to @code{gtk_signal_connect_object} except the signal handler is
connected in the ``after'' slot. This allows a signal handler to be
guaranteed to run after other signal handlers connected to the same
signal on the same object and after the class function associated with
the signal. Returns an integer identifier which can be used to refer to
the connection.
@end deftypefun

@deftypefun void gtk_signal_disconnect (GtkObject *@var{object}, gint @var{id})
Disconnects a signal handler from an object. The signal handler is
identified by the integer @var{id} which is returned by the
@code{gtk_signal_connect*} family of functions.
@end deftypefun

@deftypefun void gtk_signal_disconnect_by_data (GtkObject *@var{object}, gpointer @var{data})
Disconnects a signal handler from an object. The signal handler is
identified by the @var{data} argument specified as the @var{func_data}
argument to the @code{gtk_signal_connect*} family of functions. For the
@code{gtk_signal_connect_object*} functions, @var{data} refers to the
@var{slot_object}.

@strong{Note:} This will remove all signal handlers connected to
@var{object} which were connected using @var{data} as their
@var{func_data} argument. Multiple signal handlers may be disconnected
with this call.
@end deftypefun

@deftypefun void gtk_signal_handler_block (GtkObject *@var{object}, gint @var{id})
Blocks calling of a signal handler during signal emission. The signal
handler is identified by the integer @var{id} which is returned by the
@code{gtk_signal_connect*} family of functions. If the signal is already
blocked no change is made.
@end deftypefun

@deftypefun void gtk_signal_handler_block_by_data (GtkObject *@var{object}, gint @var{data})
Blocks calling of a signal handler during signal emission. The signal
handler is identified by the @var{data} argument specified as the
@var{func_data} argument to the @code{gtk_signal_connect*} family of
functions. For the @code{gtk_signal_connect_object*} functions,
@var{data} refers to the @var{slot_object}. If the signal is already
blocked no change is made.

@strong{Note:} This will block all signal handlers connected to
@var{object} which were connected using @var{data} as their
@var{func_data} argument. Multiple signal handlers may be blocked
with this call.
@end deftypefun

@deftypefun void gtk_signal_handler_unblock (GtkObject *@var{object}, gint @var{id})
Unblocks calling of a signal handler during signal emission. The signal
handler is identified by the integer @var{id} which is returned by the
@code{gtk_signal_connect*} family of functions. If the signal is already
unblocked no change is made.
@end deftypefun

@deftypefun void gtk_signal_handler_unblock_by_data (GtkObject *@var{object}, gint @var{data})
Unblocks calling of a signal handler during signal emission. The signal
handler is identified by the @var{data} argument specified as the
@var{func_data} argument to the @code{gtk_signal_connect*} family of
functions. For the @code{gtk_signal_connect_object*} functions,
@var{data} refers to the @var{slot_object}. If the signal is already
unblocked no change is made.

@strong{Note:} This will unblock all signal handlers connected to
@var{object} which were connected using @var{data} as their
@var{func_data} argument. Multiple signal handlers may be unblocked
with this call.
@end deftypefun

@deftypefun void gtk_signal_handlers_destroy (GtkObject *@var{object})
Destroy all of the signal handlers connected to @var{object}. There
should normally never be reason to call this function as it is called
automatically when @var{object} is destroyed.
@end deftypefun

@deftypefun void gtk_signal_default_marshaller (GtkObject *@var{object}, GtkSignalFunc @var{func}, gpointer @var{func_data}, GtkSignalParam *@var{params})
@code{gtk_signal_new} requires a callback in order to actually call a
signal handler for a particular signal. The vast majority of signals are
of the particular form:

@example
  (* std_signal) (gpointer std_arg);
@end example

@code{gtk_signal_default_marshaller} is a signal marshaller which
marshals arguments for a signal of that form.
@end deftypefun


@node Widgets, Other Objects, Signals, Top
@comment node-name, next, previous, up
@chapter Widget Overview
@cindex Widgets


Widgets are the general term used to describe user interface objects. A
widget defines a class interface that all user interface objects conform
to. This interface allows a uniform method for dealing with operations
common to all objects such as hiding and showing, size requisition and
allocation and events.

The common interface that widgets must adhere to is described by the
GtkWidget and GtkWidgetClass structure. For the purposes of using GTK
these structures can be considered read-only and, for the most part,
opaque.

All widget creation routines in GTK return pointers to GtkWidget
structures. In reality, all widget creation routines create structures
that can be viewed as equivalent to the GtkWidget structure, but often
have contain additional information. @xref{Object Implementation}

The widgets available for use are implemented in a hierarchy. Several
widgets exist solely as common bases for more specific widgets. For
example, it is not possible to create a ruler widget itself, but the
ruler widget provides a base and functionality common to the horizontal
and vertical rulers.

The available widgets (in alphabetical order):

@menu
* GtkAlignment::                The alignment widget.
* GtkArrow::                    The arrow widget.
* GtkBin::                      The bin widget.
* GtkBox::                      The box widget.
* GtkButton::                   The button widget.
* GtkCheckButton::              The check button widget.
* GtkCheckMenuItem::            The check menu item widget.
* GtkContainer::                The container widget.
* GtkDialog::                   The dialog widget.
* GtkDrawingArea::              The drawing area widget.
* GtkEntry::                    The entry widget.
* GtkFileSelection::            The file selection dialog widget.
* GtkFrame::                    The frame widget.
* GtkHBox::                     The horizontal box widget.
* GtkHRuler::                   The horizontal ruler widget.
* GtkHScale::                   The horizontal scale widget.
* GtkHScrollbar::               The horizontal scrollbar widget.
* GtkHSeparator::               The horizontal separator widget.
* GtkImage::                    The image widget.
* GtkItem::                     The item widget.
* GtkLabel::                    The label widget.
* GtkList::                     The list widget.
* GtkListItem::                 The list item widget.
* GtkMenu::                     The menu widget.
* GtkMenuBar::                  The menu bar widget.
* GtkMenuItem::                 The menu item widget.
* GtkMenuShell::                The menu shell widget.
* GtkMisc::                     The misc widget.
* GtkNotebook::                 The notebook widget.
* GtkOptionMenu::               The option menu widget.
* GtkPixmap::                   The pixmap widget.
* GtkPreview::                  The preview widget.
* GtkProgressBar::              The progress bar widget.
* GtkRadioButton::              The radio button widget.
* GtkRadioMenuItem::            The radio menu item widget.
* GtkRange::                    The range widget.
* GtkRuler::                    The ruler widget.
* GtkScale::                    The scale widget.
* GtkScrollbar::                The scrollbar widget.
* GtkScrolledWindow::           The scrolled window widget.
* GtkSeparator::                The separator widget.
* GtkTable::                    The table widget.
* GtkText::                     The text widget.
* GtkToggleButton::             The toggle button widget.
* GtkTree::                     The tree widget.
* GtkTreeItem::                 The tree item widget.
* GtkVBox::                     The vertical box widget.
* GtkViewport::                 The viewport widget.
* GtkVRuler::                   The vertical ruler widget.
* GtkVScale::                   The vertical scale widget.
* GtkVScrollbar::               The vertical scrollbar widget.
* GtkVSeparator::               The vertical separator widget.
* GtkWidget::                   The base widget type.
* GtkWindow::                   The window widget.
@end menu


@node GtkAlignment, GtkArrow, Widgets, Widgets
@comment node-name, next, previous, up
@section The alignment widget


@subsection Description

The alignment widget is a container (@pxref{GtkContainer}) derived from
the bin widget (@pxref{GtkBin}). Its entire purpose is to give the
programmer flexibility in how the child it manages is positioned when a
window is resized.

Normally, a widget is allocated at least as much size as it
requests. (@pxref{GtkContainer} for a discussion of geometry
management). When a widget is allocated more size than it requests there
is a question of how the widget should expand. By convention, most GTK
widgets expand to fill their allocated space. Sometimes this behavior is
not desired. The alignment widget allows the programmer to specify how a
widget should expand and position itself to fill the area it is
allocated.

@subsection Options

@defopt xscale
@defoptx yscale
The @var{xscale} and @var{yscale} options specify how to scale the child
widget. If the scale value is 0.0, the child widget is allocated exactly
the size it requested in that dimension. If the scale value is 1.0, the
child widget is allocated all of the space in a dimension. A scale value
of 1.0 for both x and y is equivalent to not using an alignment widget.
@end defopt

@defopt xalign
@defoptx yalign
The @var{xalign} and @var{yalign} options specify how to position the
child widget when it is not allocated all the space available to it
(because the @var{xscale} and/or @var{yscale} options are less than
1.0). If an alignment value is 0.0 the widget is positioned to the left
(or top) of its allocated space. An alignment value of 1.0 positions the
widget to the right (or bottom) of its allocated space. A common usage
is to specify @var{xalign} and @var{yalign} to be 0.5 which causes the
widget to be centered within its allocated area.
@end defopt

@subsection Signals

@subsection Functions

@deftypefun guint gtk_alignment_get_type (void)
Returns the @code{GtkAlignment} type identifier.
@end deftypefun

@deftypefun GtkWidget* gtk_alignment_new (gfloat @var{xalign}, gfloat @var{yalign}, gfloat @var{xscale}, gfloat @var{yscale})
Create a new @code{GtkAlignment} object and initialize it with the
values @var{xalign}, @var{yalign}, @var{xscale} and @var{yscale}. The
new widget is returned as a pointer to a @code{GtkWidget}
object. @code{NULL} is returned on failure.
@end deftypefun

@deftypefun void gtk_alignment_set (GtkAlignment *@var{alignment}, gfloat @var{xalign}, gfloat @var{yalign}, gfloat @var{xscale}, gfloat @var{yscale})
Set the @var{xalign}, @var{yalign}, @var{xscale} and @var{yscale} options
of an alignment widget. It is important to not set the fields of the
@code{GtkAlignment} structure directly (or, for that matter, any type
derived from @code{GtkObject}).
@end deftypefun

@gtkstdmacros{Alignment, ALIGNMENT}


@page
@node GtkArrow, GtkBin, GtkAlignment, Widgets
@comment node-name, next, previous, up
@section The arrow widget

@subsection Description

The arrow widget is derived from the misc widget (@pxref{GtkMisc}) and
is intended for use where a directional arrow (in one of the four
cardinal directions) is desired. As such, it has very limited
functionality and basically only draws itself in a particular direction
and with a particular shadow type. The arrow widget will expand to fill
all the space it is allocated.

@subsection Options

@defopt arrow_type
The @var{arrow_type} option specifies which direction the arrow will
point. It can be one of @code{GTK_ARROW_UP}, @code{GTK_ARROW_DOWN},
@code{GTK_ARROW_LEFT} or @code{GTK_ARROW_RIGHT}.
@end defopt

@defopt shadow_type
The @var{shadow_type} option specifies how to draw the shadow for the
arrow. Currently, only the @code{GTK_SHADOW_IN} and
@code{GTK_SHADOW_OUT} shadow types are supported for drawing
arrows. Other shadow types will cause nothing to be drawn.
@end defopt

@subsection Signals

@subsection Functions

@deftypefun guint gtk_arrow_get_type (void)
Returns the @code{GtkArrow} type identifier.
@end deftypefun

@deftypefun GtkWidget* gtk_arrow_new (GtkArrowType @var{arrow_type}, GtkShadowType @var{shadow_type})
Create a new @code{GtkArrow} object and initialize it with the values
@var{arrow_type} and @var{shadow_type}. The new widget is returned as a
pointer to a @code{GtkWidget} object. @code{NULL} is returned on
failure.
@end deftypefun

@deftypefun void gtk_arrow_set (GtkArrow *@var{arrow}, GtkArrowType @var{arrow_type}, GtkShadowType @var{shadow_type})
Set the @var{arrow_type} and @var{shadow_type} options of an arrow
widget. It is important to not set the fields of the @code{GtkArrow}
structure directly (or, for that matter, any type derived from
@code{GtkObject}).
@end deftypefun

@gtkstdmacros{Arrow, ARROW}


@page
@node GtkBin, GtkBox, GtkArrow, Widgets
@comment node-name, next, previous, up
@section The bin widget

@subsection Description

The bin widget is a container (@pxref{GtkContainer}) derived from the
container widget. It is an abstract base class. That is, it is not
possible to create an actual bin widget. It exists only to provide a
base of functionality for other widgets. Specifically, the bin widget
provides a base for several other widgets that contain only a single
child. These widgets include alignments (@pxref{GtkAlignment}), frames
(@pxref{GtkFrame}), items (@pxref{GtkItem}), viewports
(@pxref{GtkViewport}) and windows (@pxref{GtkWindow})

@subsection Signals

@subsection Functions

@deftypefun guint gtk_bin_get_type (void)
Returns the @code{GtkBin} type identifier.
@end deftypefun

@gtkstdmacros{Bin, BIN}


@page
@node GtkBox, GtkButton, GtkBin, Widgets
@comment node-name, next, previous, up
@section The box widget


@subsection Description

The box widget is a container (@pxref{GtkContainer}) derived from the
container widget. It is an abstract base class used by the horizontal
box (@pxref{GtkHBox}) and vertical box (@pxref{GtkVBox}) widgets to
provide a base of common functionality.

A box provides an abstraction for organizing the position and size of
widgets. Widgets in a box are layed out horizontally or vertically. By
using a box widget appropriately, a programmer can control how widgets
are positioned and how they will be allocated space when a window gets
resized.

The key attribute of boxes is that they position their children in a
single row (horizontal boxes) or column (vertical boxes). In the case of
horizontal boxes, all children are stretched vertically. The vertical
size of the box is determined by the largest vertical requisition of all
of its children. Similarly, a vertical box streches all of its children
horizontally. The horizontal size (of the vertical box) is determined by
the largest horizontal requisition of all of its children. An alignment
widget (@pxref{GtkAlignment}) can be used to control child allocation
more precisely on a per child basis.

The second attribute of boxes is how they expand children. In the case
of a horizontal box, the main control is over how children are expanded
horizontally to fill the allocated area. (The rest of this discussion
will focus on horizontal boxes but it applies to vertical boxes as
well).

There are two flags which can be set controlling how a widget is
expanded horizontally in a horizontal box. These are the @code{expand}
and @code{fill}. There operation is fairly simple. If @code{expand} is
set, the childs potentially allocated area will expand to fill available
space. If @code{fill} is set, the childs actual allocated area will be
its potentially allocated area. There is a difference between
the potentially area (which is the area the box widget sets aside for
the child) and the actual allocated area (which is the area the box
widget actual allocates for the widget via
@code{gtk_widget_size_allocate}).

The allocation of space to children occurs as follows (for horizontal
boxes):
@enumerate
@item
All children are allocated at least their requested size horizontally
and the maximum requested child size vertically.

@item
Any child with the @code{expand} flag set is allocated @code{extra_width
/ nexpand_children} extra pixels horizontally. If the @code{homogeneous}
flag was set, all children are considered to have the @code{expand} flag
set. That is, all children will be allocated the same area.The
horizontal box is a fair widget and, as such, divides up any extra
allocated space evenly among the ``expand'' children. (Those children
which have the @code{expand} flag set). The exception occurs when
@code{extra_width / nexpand_children} does not divide cleanly. The extra
space is given to the last widget.

@item
@code{spacing} number of pixels separate each child. Note: The
separation is between the potentially allocated area for each child and
not the actual allocated area. The @code{padding} value associated with
each child causes that many pixels to be left empty to each side of the
child.

@item
If a child has the @code{fill} flag set it is allocated its potentially
allocated area. If it does not, it is allocated its requested size
horizontally and centered within its potentially allocated area. Its
vertical allocation is still the maximum requested size of any child.

@item
Children placed at the start of the box are placed in order of addition
to the box from left to right in the boxes allocated area.. Children
placed at the end of the box are placed in order of addition from right
to left in the boxes allocated area.
@end enumerate

@xref{GtkHBox}, and @ref{GtkVBox}, for code examples of using horizontal
and vertical boxes.

@subsection Options

@c FIXME: options for GtkBox

@subsection Signals

@subsection Functions

@deftypefun guint gtk_box_get_type (void)
Returns the @code{GtkBox} type identifier.
@end deftypefun

@deftypefun void gtk_box_pack_start (GtkBox *@var{box}, GtkWidget *@var{child}, gint @var{expand}, gint @var{fill}, gint @var{padding})
Add @var{child} to the front of @var{box}. The flags @var{expand} and
@var{fill} and the padding value of @var{padding} are associated with
@var{child}.
@end deftypefun

@deftypefun void gtk_box_pack_end (GtkBox *@var{box}, GtkWidget *@var{child}, gint @var{expand}, gint @var{fill}, gint @var{padding})
Add @var{child} to the end of @var{box}. The flags @var{expand} and
@var{fill} and the padding value of @var{padding} are associated with
@var{child}.
@end deftypefun

@deftypefun void gtk_box_pack_start_defaults (GtkBox *@var{box}, GtkWidget *@var{widget})
A convenience function which is equivalent to the following:

@example
  gtk_box_pack_start (@var{box}, @var{widget}, TRUE, TRUE, 0);
@end example
@end deftypefun

@deftypefun void gtk_box_pack_end_defaults (GtkBox *@var{box}, GtkWidget *@var{widget})
A convenience function which is equivalent to the following:

@example
  gtk_box_pack_start (@var{box}, @var{widget}, TRUE, TRUE, 0);
@end example
@end deftypefun

@gtkstdmacros{Box, BOX}


@page
@node GtkButton, GtkCheckButton, GtkBox, Widgets
@comment node-name, next, previous, up
@section The button widget


@subsection Description

@subsection Signals

@deftypefn Signal void GtkButton::pressed (GtkButton *@var{button})
@end deftypefn

@deftypefn Signal void GtkButton::released (GtkButton *@var{button})
@end deftypefn

@deftypefn Signal void GtkButton::clicked (GtkButton *@var{button})
@end deftypefn

@deftypefn Signal void GtkButton::enter (GtkButton *@var{button})
@end deftypefn

@deftypefn Signal void GtkButton::leave (GtkButton *@var{button})
@end deftypefn

@subsection Functions

@deftypefun guint gtk_button_get_type (void)
@end deftypefun

@deftypefun GtkWidget* gtk_button_new (void)
@end deftypefun

@deftypefun GtkWidget* gtk_button_new_with_label (gchar *@var{label})
@end deftypefun

@deftypefun void gtk_button_pressed (GtkButton *@var{button})
@end deftypefun

@deftypefun void gtk_button_released (GtkButton *@var{button})
@end deftypefun

@deftypefun void gtk_button_clicked (GtkButton *@var{button})
@end deftypefun

@deftypefun void gtk_button_enter (GtkButton *@var{button})
@end deftypefun

@deftypefun void gtk_button_leave (GtkButton *@var{button})
@end deftypefun

@gtkstdmacros{Button, BUTTON}


@page
@node GtkCheckButton, GtkCheckMenuItem, GtkButton, Widgets
@comment node-name, next, previous, up
@section The check button widget


@subsection Description

@subsection Signals

@subsection Functions

@deftypefun guint gtk_check_button_get_type (void)
@end deftypefun

@deftypefun GtkWidget* gtk_check_button_new (void)
@end deftypefun

@deftypefun GtkWidget* gtk_check_button_new_with_label (gchar *@var{label})
@end deftypefun

@deftypefun GtkCheckButton* GTK_CHECK_BUTTON (gpointer @var{obj})
@end deftypefun

@deftypefun GtkCheckButtonClass* GTK_CHECK_BUTTON_CLASS (gpointer @var{class})
@end deftypefun

@deftypefun gint GTK_IS_CHECK_BUTTON (gpointer @var{obj})
@end deftypefun

@gtkstdmacros{CheckButton, CHECK_BUTTON}


@page
@node GtkCheckMenuItem, GtkContainer, GtkCheckButton, Widgets,
@comment node-name, next, previous, up
@section The check menu item widget


@subsection Description

@subsection Signals

@deftypefn Signal void GtkCheckMenuItem::toggled (GtkCheckMenuItem *@var{check_menu_item})
@end deftypefn

@subsection Functions

@deftypefun guint gtk_check_menu_item_get_type (void)
@end deftypefun

@deftypefun GtkWidget* gtk_check_menu_item_new (void)
@end deftypefun

@deftypefun GtkWidget* gtk_check_menu_item_new_with_label (gchar *@var{label})
@end deftypefun

@deftypefun void gtk_check_menu_item_set_state (GtkCheckMenuItem *@var{check_menu_item}, gint @var{state})
@end deftypefun

@deftypefun void gtk_check_menu_item_toggled (GtkCheckMenuItem *@var{check_menu_item})
@end deftypefun

@gtkstdmacros{CheckMenuItem, CHECK_MENU_ITEM}


@page
@node GtkContainer, GtkDialog, GtkCheckMenuItem, Widgets
@comment node-name, next, previous, up
@section The container widget


@subsection Description

@subsection Signals

@deftypefn Signal void GtkContainer::add (GtkContainer *@var{container}, GtkWidget *@var{widget})
@end deftypefn

@deftypefn Signal void GtkContainer::remove (GtkContainer *@var{container}, GtkWidget *@var{widget})
@end deftypefn

@deftypefn Signal void GtkContainer::need_resize (GtkContainer *@var{container}, GtkWidget *@var{widget})
@end deftypefn

@deftypefn Signal void GtkContainer::foreach (GtkContainer *@var{container}, GtkCallback @var{callback}, gpointer @var{callback_data})
@end deftypefn

@deftypefn Signal gint GtkContainer::focus (GtkContainer *@var{container}, GtkDirectionType @var{direction})
@end deftypefn

@subsection Functions

@deftypefun guint gtk_container_get_type (void)
@end deftypefun

@deftypefun void gtk_container_border_width (GtkContainer *@var{container}, gint @var{border_width})
@end deftypefun

@deftypefun void gtk_container_add (GtkContainer *@var{container}, GtkWidget *@var{widget})
@end deftypefun

@deftypefun void gtk_container_remove (GtkContainer *@var{container}, GtkWidget *@var{widget})
@end deftypefun

@deftypefun void gtk_container_disable_resize (GtkContainer *@var{container})
@end deftypefun

@deftypefun void gtk_container_enable_resize (GtkContainer *@var{container})
@end deftypefun

@deftypefun void gtk_container_block_resize (GtkContainer *@var{container})
@end deftypefun

@deftypefun void gtk_container_unblock_resize (GtkContainer *@var{container})
@end deftypefun

@deftypefun gint gtk_container_need_resize (GtkContainer *@var{container}, GtkWidget *@var{widget})
@end deftypefun

@deftypefun void gtk_container_check_resize (GtkContainer *@var{container}, GtkWidget *@var{widget})
@end deftypefun

@deftypefun void gtk_container_foreach (GtkContainer *@var{container}, GtkCallback @var{callback}, gpointer @var{callback_data})
@end deftypefun

@deftypefun void gtk_container_focus (GtkContainer *@var{container}, GtkDirectionType @var{direction})
@end deftypefun

@deftypefun GList* gtk_container_children (GtkContainer @var{container})
@end deftypefun

@gtkstdmacros{Container, CONTAINER}


@page
@node GtkDialog, GtkDrawingArea, GtkContainer, Widgets
@comment node-name, next, previous, up
@section The dialog widget


@subsection Description

@subsection Signals

@subsection Functions

@deftypefun guint gtk_dialog_get_type (void)
@end deftypefun

@deftypefun GtkWidget* gtk_dialog_new (void)
@end deftypefun

@gtkstdmacros{Dialog, DIALOG}


@page
@node GtkDrawingArea, GtkEntry, GtkDialog, Widgets
@comment node-name, next, previous, up
@section The drawing area widget


@subsection Description

@subsection Signals

@subsection Functions

@deftypefun guint gtk_drawing_area_get_type (void)
@end deftypefun

@deftypefun GtkWidget* gtk_drawing_area_new (void)
@end deftypefun

@deftypefun void gtk_drawing_area_size (GtkDrawingArea *@var{darea}, gint @var{width}, gint @var{height})
@end deftypefun

@gtkstdmacros{DrawingArea, DRAWING_AREA}


@page
@node GtkEntry, GtkFileSelection, GtkDrawingArea, Widgets
@comment node-name, next, previous, up
@section The entry widget


@subsection Description

@subsection Signals

@deftypefn Signal void GtkEntry::insert (GtkEntry *@var{entry}, gchar *@var{text}, gint @var{length}, gint *@var{position})
@end deftypefn

@deftypefn Signal void GtkEntry::delete (GtkEntry *@var{entry}, gint @var{start_pos}, gint @var{end_pos})
@end deftypefn

@deftypefn Signal void GtkEntry::changed (GtkEntry *@var{entry})
@end deftypefn

@subsection Functions

@deftypefun guint gtk_entry_get_type (void)
@end deftypefun

@deftypefun GtkWidget* gtk_entry_new (void)
@end deftypefun

@deftypefun void gtk_entry_set_text (GtkEntry *@var{entry}, gchar *@var{text})
@end deftypefun

@deftypefun void gtk_entry_append_text (GtkEntry *@var{entry}, gchar *@var{text})
@end deftypefun

@deftypefun void gtk_entry_prepend_text (GtkEntry *@var{entry}, gchar *@var{text})
@end deftypefun

@deftypefun void gtk_entry_set_position (GtkEntry *@var{entry}, gint @var{position})
@end deftypefun

@deftypefun gchar* gtk_entry_get_text (GtkEntry *@var{entry})
@end deftypefun

@gtkstdmacros{Entry, ENTRY}


@page
@node GtkFileSelection, GtkFrame, GtkEntry, Widgets
@comment node-name, next, previous, up
@section The file selection dialog widget


@subsection Description

@subsection Signals

@subsection Functions

@deftypefun guint gtk_file_selection_get_Type (void)
@end deftypefun

@deftypefun GtkWidget* gtk_file_selection_new (gchar *@var{title})
@end deftypefun

@deftypefun void gtk_file_selection_set_filename (GtkFileSelection *@var{filesel}, gchar *@var{filename})
@end deftypefun

@deftypefun gchar* gtk_file_selection_get_filename (GtkFileSelection *@var{filesel})
@end deftypefun

@gtkstdmacros{FileSelection, FILE_SELECTION}


@page
@node GtkFrame, GtkHBox, GtkFileSelection, Widgets
@comment node-name, next, previous, up
@section The frame widget


@subsection Description

@subsection Signals

@subsection Functions

@deftypefun guint gtk_frame_get_type (void)
@end deftypefun

@deftypefun GtkWidget* gtk_frame_new (gchar *@var{label})
@end deftypefun

@deftypefun void gtk_frame_set_label (GtkFrame *@var{frame}, gchar *@var{label})
@end deftypefun

@deftypefun void gtk_frame_set_label_align (GtkFrame *@var{frame}, gfloat @var{xalign}, gfloat @var{yalign})
@end deftypefun

@deftypefun void gtk_frame_set_shadow_type (GtkFrame *@var{frame}, GtkShadowType @var{type})
@end deftypefun

@gtkstdmacros{Frame, FRAME}


@page
@node GtkHBox, GtkHRuler, GtkFrame, Widgets
@comment node-name, next, previous, up
@section The horizontal box widget


@subsection Description

@subsection Signals

@subsection Functions

@deftypefun guint gtk_hbox_get_type (void)
@end deftypefun

@deftypefun GtkWidget* gtk_hbox_new (gint @var{homogeneous}, gint @var{spacing})
@end deftypefun

@gtkstdmacros{HBox, HBOX}


@page
@node GtkHRuler, GtkHScale, GtkHBox, Widgets
@comment node-name, next, previous, up
@section The horizontal ruler widget


@subsection Description

@subsection Signals

@subsection Functions

@deftypefun guint gtk_hruler_get_type (void)
@end deftypefun

@deftypefun GtkWidget* gtk_hruler_new (void)
@end deftypefun

@gtkstdmacros{HRuler, HRULER}


@page
@node GtkHScale, GtkHScrollbar, GtkHRuler, Widgets
@comment node-name, next, previous, up
@section The horizontal scale widget


@subsection Description

@subsection Signals

@subsection Functions

@deftypefun guint gtk_hscale_get_type (void)
@end deftypefun

@deftypefun GtkWidget* gtk_hscale_new (GtkAdjustment *@var{adjustment})
@end deftypefun

@gtkstdmacros{HScale, HSCALE}


@page
@node GtkHScrollbar, GtkHSeparator, GtkHScale, Widgets
@comment node-name, next, previous, up
@section The horizontal scrollbar widget


@subsection Description

@subsection Signals

@subsection Functions

@deftypefun guint gtk_hscrollbar_get_type (void)
@end deftypefun

@deftypefun GtkWidget* gtk_hscrollbar_new (GtkAdjustment *@var{adjustment})
@end deftypefun

@gtkstdmacros{HScrollbar, HSCROLLBAR}


@page
@node GtkHSeparator, GtkImage, GtkHScrollbar, Widgets
@comment node-name, next, previous, up
@section The horizontal separator widget


@subsection Description

@subsection Signals

@subsection Functions

@deftypefun guint gtk_hseparator_get_type (void)
@end deftypefun

@deftypefun GtkWidget* gtk_hseparator_new (void)
@end deftypefun

@gtkstdmacros{HSeparator, HSEPARATOR}


@page
@node GtkImage, GtkItem, GtkHSeparator, Widgets
@comment node-name, next, previous, up
@section The image widget


@subsection Description

@subsection Signals

@subsection Functions

@deftypefun guint gtk_image_get_type (void)
@end deftypefun

@deftypefun GtkWidget* gtk_image_new (GdkImage *@var{val})
@end deftypefun

@deftypefun void gtk_image_set (GtkImage *@var{image}, GdkImage *@var{val})
@end deftypefun

@deftypefun void gtk_image_get (GtkImage *@var{image}, GdkImage **@var{val})
@end deftypefun

@gtkstdmacros{Image, IMAGE}


@page
@node GtkItem, GtkLabel, GtkImage, Widgets
@comment node-name, next, previous, up
@section The item widget


@subsection Description

@subsection Signals

@deftypefn Signal void GtkItem::select (GtkItem *@var{item})
@end deftypefn

@deftypefn Signal void GtkItem::deselect (GtkItem *@var{item})
@end deftypefn

@deftypefn Signal void GtkItem::toggle (GtkItem *@var{toggle})
@end deftypefn

@subsection Functions

@deftypefun guint gtk_item_get_type (void)
@end deftypefun

@deftypefun void gtk_item_select (GtkItem *@var{item})
@end deftypefun

@deftypefun void gtk_item_deselect (GtkItem *@var{item})
@end deftypefun

@deftypefun void gtk_item_toggle (GtkItem *@var{item})
@end deftypefun

@gtkstdmacros{Item, ITEM}


@page
@node GtkLabel, GtkList, GtkItem, Widgets
@comment node-name, next, previous, up
@section The label widget


@subsection Description

@subsection Signals

@subsection Functions

@deftypefun guint gtk_label_get_type (void)
@end deftypefun

@deftypefun GtkWidget* gtk_label_new (GtkLabel *@var{label}, gchar *@var{str})
@end deftypefun

@deftypefun void gtk_label_set (GtkLabel *@var{label}, gchar *@var{str})
@end deftypefun

@deftypefun void gtk_label_get (GtkLabel *@var{label}, gchar **@var{str})
@end deftypefun

@gtkstdmacros{Label, LABEL}


@page
@node GtkList, GtkListItem, GtkLabel, Widgets
@comment node-name, next, previous, up
@section The list widget


@subsection Description

@subsection Signals

@deftypefn Signal void GtkList::selection_changed (GtkList *@var{list})
@end deftypefn

@deftypefn Signal void GtkList::select_child (GtkList *@var{list}, GtkWidget *@var{child})
@end deftypefn

@deftypefn Signal void GtkList::unselect_child (GtkList *@var{list}, GtkWidget *@var{child})
@end deftypefn

@subsection Functions

@deftypefun guint gtk_list_get_type (void)
@end deftypefun

@deftypefun GtkWidget* gtk_list_new (void)
@end deftypefun

@deftypefun void gtk_list_insert_items (GtkList *@var{list}, GList *@var{items}, gint @var{position})
@end deftypefun

@deftypefun void gtk_list_append_items (GtkList *@var{list}, GList *@var{items})
@end deftypefun

@deftypefun void gtk_list_prepend_items (GtkList *@var{list}, GList *@var{items})
@end deftypefun

@deftypefun void gtk_list_remove_items (GtkList *@var{list}, GList *@var{items})
@end deftypefun

@deftypefun void gtk_list_clear_items (GtkList *@var{list}, gint @var{start}, gint @var{end})
@end deftypefun

@deftypefun void gtk_list_select_item (GtkList *@var{list}, gint @var{item})
@end deftypefun

@deftypefun void gtk_list_unselect_item (GtkList *@var{list}, gint @var{item})
@end deftypefun

@deftypefun void gtk_list_select_child (GtkList *@var{list}, GtkWidget *@var{child})
@end deftypefun

@deftypefun void gtk_list_unselect_child (GtkList *@var{list}, GtkWidget *@var{child})
@end deftypefun

@deftypefun gint gtk_list_child_position (GtkList *@var{list}, GtkWidget *@var{child})
@end deftypefun

@deftypefun void gtk_list_set_selection_mode (GtkList *@var{list}, GtkSelectionMode @var{mode})
@end deftypefun

@gtkstdmacros{List, LIST}


@page
@node GtkListItem, GtkMenu, GtkList, Widgets
@comment node-name, next, previous, up
@section The list item widget


@subsection Description

@subsection Signals

@subsection Functions

@deftypefun guint gtk_list_item_get_type (void)
@end deftypefun

@deftypefun GtkWidget* gtk_list_item_new (void)
@end deftypefun

@deftypefun GtkWidget* gtk_list_item_new_with_label (gchar *@var{label})
@end deftypefun

@deftypefun void gtk_list_item_select (GtkListItem *@var{list_item})
@end deftypefun

@deftypefun void gtk_list_item_deselect (GtkListItem *@var{list_item})
@end deftypefun

@gtkstdmacros{ListItem, LIST_ITEM}


@page
@node GtkMenu, GtkMenuBar, GtkListItem, Widgets
@comment node-name, next, previous, up
@section The menu widget


@subsection Description

@subsection Signals

@subsection Functions

@deftypefun guint gtk_menu_get_type (void)
@end deftypefun

@deftypefun GtkWidget* gtk_menu_new (void)
@end deftypefun

@deftypefun void gtk_menu_append (GtkMenu *@var{menu}, GtkWidget *@var{child})
@end deftypefun

@deftypefun void gtk_menu_prepend (GtkMenu *@var{menu}, GtkWidget *@var{child})
@end deftypefun

@deftypefun void gtk_menu_insert (GtkMenu *@var{menu}, GtkWidget *@var{child}, gint @var{position})
@end deftypefun

@deftypefun void gtk_menu_popup (GtkMenu *@var{menu}, GtkWidget *@var{parent_menu_shell}, GtkWidget *@var{parent_menu_item}, GtkMenuPositionFunc @var{func}, gpointer @var{data}, gint @var{button})
@end deftypefun

@deftypefun void gtk_menu_popdown (GtkMenu *@var{menu})
@end deftypefun

@deftypefun GtkWidget* gtk_menu_get_active (GtkMenu *@var{menu})
@end deftypefun

@deftypefun void gtk_menu_set_active (GtkMenu *@var{menu})
@end deftypefun

@deftypefun void gtk_menu_set_accelerator_table (GtkMenu *@var{menu}, GtkAcceleratorTable *@var{table})
@end deftypefun

@gtkstdmacros{Menu, MENU}


@page
@node GtkMenuBar, GtkMenuItem, GtkMenu, Widgets
@comment node-name, next, previous, up
@section The menu bar widget


@subsection Description

@subsection Signals

@subsection Functions

@deftypefun guint gtk_menu_bar_get_type (void)
@end deftypefun

@deftypefun GtkWidget* gtk_menu_bar_new (void)
@end deftypefun

@deftypefun void gtk_menu_bar_append (GtkMenuBar *@var{menu_bar}, GtkWidget *@var{child})
@end deftypefun

@deftypefun void gtk_menu_bar_prepend (GtkMenuBar *@var{menu_bar}, GtkWidget *@var{child})
@end deftypefun

@deftypefun void gtk_menu_bar_insert (GtkMenuBar *@var{menu_bar}, GtkWidget *@var{child}, gint @var{position})
@end deftypefun

@gtkstdmacros{MenuBar, MENU_BAR}


@page
@node GtkMenuItem, GtkMenuShell, GtkMenuBar, Widgets
@comment node-name, next, previous, up
@section The menu item widget


@subsection Description

@subsection Signals

@deftypefn Signal void GtkMenuItem::activate (GtkMenuItem *@var{menu_item})
@end deftypefn

@subsection Functions

@deftypefun guint gtk_menu_item_get_type (void)
@end deftypefun

@deftypefun GtkWidget* gtk_menu_item_new (void)
@end deftypefun

@deftypefun GtkWidget* gtk_menu_item_new_with_label (gchar *@var{label})
@end deftypefun

@deftypefun void gtk_menu_item_set_submenu (GtkMenuItem *@var{menu_item}, GtkWidget *@var{submenu})
@end deftypefun

@deftypefun void gtk_menu_item_set_placement (GtkMenuItem *@var{menu_item}, GtkSubmenuPlacement @var{placement})
@end deftypefun

@deftypefun void gtk_menu_item_accelerator_size (GtkMenuItem *@var{menu_item})
@end deftypefun

@deftypefun void gtk_menu_item_accelerator_text (GtkMenuItem *@var{menu_item}, gchar *@var{buffer})
@end deftypefun

@deftypefun void gtk_menu_item_configure (GtkMenuItem *@var{menu_item}, gint @var{show_toggle_indicator}, gint @var{show_submenu_indicator})
@end deftypefun

@deftypefun void gtk_menu_item_select (GtkMenuItem *@var{menu_item})
@end deftypefun

@deftypefun void gtk_menu_item_deselect (GtkMenuItem *@var{menu_item})
@end deftypefun

@deftypefun void gtk_menu_item_activate (GtkMenuItem *@var{menu_item})
@end deftypefun

@gtkstdmacros{MenuItem, MENU_ITEM}


@page
@node GtkMenuShell, GtkMisc, GtkMenuItem, Widgets
@comment node-name, next, previous, up
@section The menu shell widget


@subsection Description

@subsection Signals

@deftypefn Signal void GtkMenuShell::deactivate (GtkMenuShell *@var{menu_shell})
@end deftypefn

@subsection Functions

@deftypefun guint gtk_menu_shell_get_type (void)
@end deftypefun

@deftypefun void gtk_menu_shell_append (GtkMenuShell *@var{menu_shell}, GtkWidget *@var{child})
@end deftypefun

@deftypefun void gtk_menu_shell_prepend (GtkMenuShell *@var{menu_shell}, GtkWidget *@var{child})
@end deftypefun

@deftypefun void gtk_menu_shell_insert (GtkMenuShell *@var{menu_shell}, GtkWidget *@var{child}, gint @var{position})
@end deftypefun

@deftypefun void gtk_menu_shell_deactivate (GtkMenuShell *@var{menu_shell})
@end deftypefun

@gtkstdmacros{MenuShell, MENU_SHELL}


@page
@node GtkMisc, GtkNotebook, GtkMenuShell, Widgets
@comment node-name, next, previous, up
@section The misc widget


@subsection Description

@subsection Signals

@subsection Functions

@deftypefun guint gtk_misc_get_type (void)
@end deftypefun

@deftypefun void gtk_misc_set_alignment (GtkMisc *@var{misc}, gfloat @var{xalign}, gfloat @var{yalign})
@end deftypefun

@deftypefun void gtk_misc_set_padding (GtkMisc *@var{misc}, gint @var{xpad}, gint @var{ypad})
@end deftypefun

@gtkstdmacros{Misc, MISC}


@page
@node GtkNotebook, GtkOptionMenu, GtkMisc, Widgets
@comment node-name, next, previous, up
@section The notebook widget


@subsection Description

@subsection Signals

@subsection Functions

@deftypefun guint gtk_notebook_get_type (void)
@end deftypefun

@deftypefun GtkWidget* gtk_notebook_new (void)
@end deftypefun

@deftypefun void gtk_notebook_append_page (GtkNotebook *@var{notebook}, GtkWidget *@var{child}, GtkWidget *@var{tab_label})
@end deftypefun

@deftypefun void gtk_notebook_prepend_page (GtkNotebook *@var{notebook}, GtkWidget *@var{child}, GtkWidget *@var{tab_label})
@end deftypefun

@deftypefun void gtk_notebook_insert_page (GtkNotebook *@var{notebook}, GtkWidget *@var{child}, GtkWidget *@var{tab_label}, gint @var{position})
@end deftypefun

@deftypefun void gtk_notebook_remove_page (GtkNotebook *@var{notebook}, gint @var{page_num})
@end deftypefun

@deftypefun void gtk_notebook_set_page (GtkNotebook *@var{notebook}, gint @var{page_num})
@end deftypefun

@deftypefun void gtk_notebook_next_page (GtkNotebook *@var{notebook})
@end deftypefun

@deftypefun void gtk_notebook_prev_page (GtkNotebook *@var{notebook})
@end deftypefun

@deftypefun void gtk_notebook_set_tab_pos (GtkNotebook *@var{notebook}, GtkPositionType @var{pos})
@end deftypefun

@deftypefun void gtk_notebook_set_show_tabs (GtkNotebook *@var{notebook}, gint @var{show_tabs})
@end deftypefun

@deftypefun void gtk_notebook_set_show_border (GtkNotebook *@var{notebook}, gint @var{show_border})
@end deftypefun

@gtkstdmacros{Notebook, NOTEBOOK}


@page
@node GtkOptionMenu, GtkPixmap, GtkNotebook, Widgets
@comment node-name, next, previous, up
@section The option menu widget


@subsection Description

@subsection Signals

@subsection Functions

@deftypefun guint gtk_option_menu_get_type (void)
@end deftypefun

@deftypefun GtkWidget* gtk_option_menu_new (void)
@end deftypefun

@deftypefun GtkWidget* gtk_option_menu_get_menu (GtkOptionMenu *@var{option_menu})
@end deftypefun

@deftypefun void gtk_option_menu_set_menu (GtkOptionMenu *@var{option_menu}, GtkWidget *@var{menu})
@end deftypefun

@deftypefun void gtk_option_menu_remove_menu (GtkOptionMenu *@var{option_menu})
@end deftypefun

@deftypefun void gtk_option_menu_set_history (GtkOptionMenu *@var{option_menu}, gint @var{index})
@end deftypefun

@gtkstdmacros{OptionMenu, OPTION_MENU}


@page
@node GtkPixmap, GtkPreview, GtkOptionMenu, Widgets
@comment node-name, next, previous, up
@section The pixmap widget


@subsection Description

@subsection Signals

@subsection Functions

@deftypefun guint gtk_pixmap_get_type (void)
@end deftypefun

@deftypefun GtkWidget* gtk_pixmap_new (GdkPixmap *@var{normal}, GdkPixmap *@var{active}, GdkPixmap *@var{prelight}, GdkPixmap *@var{selected}, GdkPixmap *@var{insensitive})
@end deftypefun

@deftypefun void gtk_pixmap_set (GtkPixmap *@var{pixmap}, GdkPixmap *@var{val}, GtkStateType @var{state})
@end deftypefun

@deftypefun void gtk_pixmap_get (GtkPixmap *@var{pixmap}, GdkPixmap **@var{val}, GtkStateType @var{state})
@end deftypefun

@gtkstdmacros{Pixmap, PIXMAP}


@page
@node GtkPreview, GtkProgressBar, GtkPixmap, Widgets
@comment node-name, next, previous, up
@section The preview widget


@subsection Description

@subsection Signals

@subsection Functions

@deftypefun guint gtk_preview_get_type (void)
@end deftypefun

@deftypefun void gtk_preview_uninit (void)
@end deftypefun

@deftypefun GtkWidget* gtk_preview_new (GtkPreviewType @var{type})
@end deftypefun

@deftypefun void gtk_preview_size (GtkPreview *@var{preview}, gint @var{width}, gint @var{height})
@end deftypefun

@deftypefun void gtk_preview_put (GtkPreview *@var{preview}, GdkWindow *@var{window}, GdkGC *@var{gc}, gint @var{srcx}, gint @var{srcy}, gint @var{destx}, gint @var{desty}, gint @var{width}, gint @var{height})
@end deftypefun

@deftypefun void gtk_preview_put_row (GtkPreview *@var{preview}, guchar *@var{src}, guchar *@var{dest}, gint @var{x}, gint @var{y}, gint @var{w})
@end deftypefun

@deftypefun void gtk_preview_draw_row (GtkPreview *@var{preview}, guchar @var{data}, gint @var{x}, gint @var{y}, gint @var{w})
@end deftypefun

@deftypefun void gtk_preview_set_expand (GtkPreview *@var{preview}, gint @var{expand})
@end deftypefun

@deftypefun void gtk_preview_set_gamma (double @var{gamma})
@end deftypefun

@deftypefun void gtk_preview_set_color_cube (guint @var{nred_shades}, guint @var{ngreen_shades}, guint @var{nblue_shades}, guint @var{ngray_shades})
@end deftypefun

@deftypefun void gtk_preview_set_install_cmap (gint @var{install_cmap})
@end deftypefun

@deftypefun void gtk_preview_set_reserved (gint @var{nreserved})
@end deftypefun

@deftypefun GdkVisual* gtk_preview_get_visual (void)
@end deftypefun

@deftypefun GdkColormap* gtk_preview_get_cmap (void)
@end deftypefun

@deftypefun GtkPreviewInfo* gtk_preview_get_info (void)
@end deftypefun

@gtkstdmacros{Preview, PREVIEW}


@page
@node GtkProgressBar, GtkRadioButton, GtkPreview, Widgets
@comment node-name, next, previous, up
@section The progress bar widget


@subsection Description

@subsection Signals

@subsection Functions

@deftypefun guint gtk_progress_bar_get_type (void)
@end deftypefun

@deftypefun GtkWidget* gtk_progress_bar_new (void)
@end deftypefun

@deftypefun void gtk_progress_bar_update (GtkProgressBar *@var{pbar}, gfloat @var{percentage})
@end deftypefun

@gtkstdmacros{ProgressBar, PROGRESS_BAR}


@page
@node GtkRadioButton, GtkRadioMenuItem, GtkProgressBar, Widgets
@comment node-name, next, previous, up
@section The radio button widget


@subsection Description

@subsection Signals

@subsection Functions

@deftypefun guint gtk_radio_button_get_type (void)
@end deftypefun

@deftypefun GtkWidget* gtk_radio_button_new (GSList *@var{group})
@end deftypefun

@deftypefun GtkWidget* gtk_radio_button_new_with_label (GSList *@var{group}, gchar *@var{label})
@end deftypefun

@deftypefun GSList* gtk_radio_button_group (GtkRadioButton *@var{radio_button})
@end deftypefun

@gtkstdmacros{RadioButton, RADIO_BUTTON}


@page
@node GtkRadioMenuItem, GtkRange, GtkRadioButton, Widgets
@comment node-name, next, previous, up
@section The radio button widget


@subsection Description

@subsection Signals

@subsection Functions

@deftypefun guint gtk_radio_menu_item_get_type (void)
@end deftypefun

@deftypefun GtkWidget* gtk_radio_menu_item_new (GSList *@var{group})
@end deftypefun

@deftypefun GtkWidget* gtk_radio_menu_item_new_with_label (GSList *@var{group}, gchar *@var{label})
@end deftypefun

@deftypefun GSList* gtk_radio_menu_item_group (GtkRadioMenuItem *@var{radio_menu_item})
@end deftypefun

@gtkstdmacros{RadioMenuItem, RADIO_MENU_ITEM}


@page
@node GtkRange, GtkRuler, GtkRadioMenuItem, Widgets
@comment node-name, next, previous, up
@section The range widget


@subsection Description

@subsection Signals

@subsection Functions

@deftypefun guint gtk_range_get_type (void)
@end deftypefun

@deftypefun GtkAdjustment* gtk_range_get_adjustment (GtkRange *@var{range})
@end deftypefun

@deftypefun void gtk_range_set_update_policy (GtkRange *@var{range}, GtkUpdatePolicy @var{policy})
@end deftypefun

@deftypefun void gtk_range_set_adjustment (GtkRange *@var{range}, GtkAdjustment *@var{adjustment})
@end deftypefun

@deftypefun void gtk_range_draw_background (GtkRange *@var{range})
@end deftypefun

@deftypefun void gtk_range_draw_trough (GtkRange *@var{range})
@end deftypefun

@deftypefun void gtk_range_draw_slider (GtkRange *@var{range})
@end deftypefun

@deftypefun void gtk_range_draw_step_forw (GtkRange *@var{range})
@end deftypefun

@deftypefun void gtk_range_draw_step_back (GtkRange *@var{range})
@end deftypefun

@deftypefun void gtk_range_slider_update (GtkRange *@var{range})
@end deftypefun

@deftypefun gint gtk_range_trough_click (GtkRange *@var{range}, gint @var{x}, gint @var{y})
@end deftypefun

@deftypefun void gtk_range_default_hslider_update (GtkRange *@var{range})
@end deftypefun

@deftypefun void gtk_range_default_vslider_update (GtkRange *@var{range})
@end deftypefun

@deftypefun gint gtk_range_default_htrough_click (GtkRange *@var{range}, gint @var{x}, gint @var{y})
@end deftypefun

@deftypefun gint gtk_range_default_vtrough_click (GtkRange *@var{range}, gint @var{x}, gint @var{y})
@end deftypefun

@deftypefun void gtk_range_default_hmotion (GtkRange *@var{range}, gint @var{xdelta}, gint @var{ydelta})
@end deftypefun

@deftypefun void gtk_range_default_vmotion (GtkRange *@var{range}, gint @var{xdelta}, gint @var{ydelta})
@end deftypefun

@deftypefun gfloat gtk_range_calc_value (GtkRange *@var{ragne}, gint @var{position})
@end deftypefun

@gtkstdmacros{Range, RANGE}


@page
@node GtkRuler, GtkScale, GtkRange, Widgets
@comment node-name, next, previous, up
@section The ruler widget


@subsection Description

@subsection Signals

@subsection Functions

@deftypefun guint gtk_ruler_get_type (void)
@end deftypefun

@deftypefun void gtk_ruler_set_metric (GtkRuler *@var{ruler}, GtkMetricType @var{metric})
@end deftypefun

@deftypefun void gtk_ruler_set_range (GtkRuler *@var{ruler}, gfloat @var{lower}, gfloat @var{upper}, gfloat @var{position}, gfloat @var{max_size})
@end deftypefun

@deftypefun void gtk_ruler_draw_ticks (GtkRuler *@var{ruler})
@end deftypefun

@deftypefun void gtk_ruler_draw_pos (GtkRuler *@var{ruler})
@end deftypefun

@gtkstdmacros{Ruler, RULER}


@page
@node GtkScale, GtkScrollbar, GtkRuler, Widgets
@comment node-name, next, previous, up
@section The scale widget


@subsection Description

@subsection Signals

@subsection Functions

@deftypefun guint gtk_scale_get_type (void)
@end deftypefun

@deftypefun void gtk_scale_set_digits (GtkScale *@var{scale}, gint @var{digits})
@end deftypefun

@deftypefun void gtk_scale_set_draw_value (GtkScale *@var{scale}, gint @var{draw_value})
@end deftypefun

@deftypefun void gtk_scale_set_value_pos (GtkScale *@var{scale}, gint @var{pos})
@end deftypefun

@deftypefun gint gtk_scale_value_width (GtkScale *@var{scale})
@end deftypefun

@deftypefun void gtk_scale_draw_value (GtkScale *@var{scale})
@end deftypefun

@gtkstdmacros{Scale, SCALE}


@page
@node GtkScrollbar, GtkScrolledWindow, GtkScale, Widgets
@comment node-name, next, previous, up
@section The scrollbar widget


@subsection Description

@subsection Signals

@subsection Functions

@deftypefun guint gtk_scrollbar_get_type (void)
@end deftypefun

@gtkstdmacros{Scrollbar, SCROLLBAR}


@page
@node GtkScrolledWindow, GtkSeparator, GtkScrollbar, Widgets
@comment node-name, next, previous, up
@section The scrolled window widget


@subsection Description

@subsection Signals

@subsection Functions

@deftypefun guint gtk_scrolled_window_get_type (void)
@end deftypefun

@deftypefun GtkWidget* gtk_scrolled_window_new (GtkAdjustment *@var{hadjustment}, GtkAdjustment *@var{vadjustment})
@end deftypefun

@deftypefun GtkAdjustment* gtk_scrolled_window_get_hadjustment (GtkScrolledWindow *@var{scrolled_window})
@end deftypefun

@deftypefun GtkAdjustment* gtk_scrolled_window_get_vadjustment (GtkScrolledWindow *@var{scrolled_window})
@end deftypefun

@deftypefun void gtk_scrolled_window_set_policy (GtkScrolledWindow *@var{scrolled_window}, GtkPolicyType @var{hscrollbar_policy}, GtkPolicyType @var{vscrollbar_policy})
@end deftypefun

@gtkstdmacros{ScrolledWindow, SCROLLED_WINDOW}


@page
@node GtkSeparator, GtkTable, GtkScrolledWindow, Widgets
@comment node-name, next, previous, up
@section The separator widget


@subsection Description

@subsection Signals

@subsection Functions

@deftypefun guint gtk_separator_get_type (void)
@end deftypefun

@gtkstdmacros{Separator, SEPARATOR}


@page
@node GtkTable, GtkText, GtkSeparator, Widgets
@comment node-name, next, previous, up
@section The table widget


@subsection Description

@subsection Signals

@subsection Functions

@deftypefun guint gtk_table_get_type (void)
@end deftypefun

@deftypefun GtkWidget* gtk_table_new (gint @var{rows}, gint @var{columns}, gint @var{homogeneous})
@end deftypefun

@deftypefun void gtk_table_attach (GtkTable *@var{table}, GtkWidget *@var{child}, gint @var{left_attach}, gint @var{right_attach}, gint @var{top_attach}, gint @var{bottom_attach}, gint @var{xoptions}, gint @var{yoptions}, gint @var{xpadding}, gint @var{ypadding})
@end deftypefun

@deftypefun void gtk_table_attach_defaults (GtkTable *@var{table}, GtkWidget *@var{widget}, gint @var{left_attach}, gint @var{right_attach}, gint @var{top_attach}, gint @var{bottom_attach})
@end deftypefun

@deftypefun void gtk_table_set_row_spacing (GtkTable *@var{table}, gint @var{row}, gint @var{spacing})
@end deftypefun

@deftypefun void gtk_table_set_col_spacing (GtkTable *@var{table}, gint @var{col}, gint @var{spacing})
@end deftypefun

@deftypefun void gtk_table_set_row_spacings (GtkTable *@var{table}, gint @var{spacing})
@end deftypefun

@deftypefun void gtk_table_set_col_spacings (GtkTable *@var{table}, gint @var{spacing})
@end deftypefun

@gtkstdmacros{Table, TABLE}


@page
@node GtkText, GtkToggleButton, GtkTable, Widgets
@comment node-name, next, previous, up
@section The text widget


@subsection Description

@subsection Signals

@subsection Functions

@deftypefun guint gtk_text_get_type (void)
@end deftypefun

@gtkstdmacros{Text, TEXT}


@page
@node GtkToggleButton, GtkTree, GtkText, Widgets
@comment node-name, next, previous, up
@section The toggle button widget


@subsection Description

@subsection Signals

@deftypefn Signal void GtkToggleButton::toggled (GtkToggleButton *@var{toggle_button})
@end deftypefn

@subsection Functions

@deftypefun guint gtk_toggle_button_get_type (void)
@end deftypefun

@deftypefun GtkWidget* gtk_toggle_button_new (void)
@end deftypefun

@deftypefun GtkWidget* gtk_toggle_button_new_with_label (gchar *@var{label})
@end deftypefun

@deftypefun void gtk_toggle_button_set_mode (GtkToggleButton *@var{toggle_button}, gint @var{draw_indicator})
@end deftypefun

@deftypefun void gtk_toggle_button_set_state (GtkToggleButton *@var{toggle_button}, gint @var{state})
@end deftypefun

@deftypefun void gtk_toggle_button_toggled (GtkToggleButotn *@var{toggle_button})
@end deftypefun

@gtkstdmacros{ToggleButton, TOGGLE_BUTTON}


@page
@node GtkTree, GtkTreeItem, GtkToggleButton, Widgets
@comment node-name, next, previous, up
@section The tree widget


@subsection Description

@subsection Signals

@subsection Functions

@deftypefun guint gtk_tree_get_type (void)
@end deftypefun

@gtkstdmacros{Tree, TREE}


@page
@node GtkTreeItem, GtkVBox, GtkTree, Widgets
@comment node-name, next, previous, up
@section The tree item widget


@subsection Description

@subsection Signals

@subsection Functions

@deftypefun guint gtk_tree_item_get_type (void)
@end deftypefun

@gtkstdmacros{TreeItem, TREE_ITEM}


@page
@node GtkVBox, GtkViewport, GtkTreeItem, Widgets
@comment node-name, next, previous, up
@section The vertical box widget


@subsection Description

@subsection Signals

@subsection Functions

@deftypefun guint gtk_vbox_get_type (void)
@end deftypefun

@deftypefun GtkWidget* gtk_vbox_new (gint @var{homogeneous}, gint @var{spacing})
@end deftypefun

@gtkstdmacros{VBox, VBOX}


@page
@node GtkViewport, GtkVRuler, GtkVBox, Widgets
@comment node-name, next, previous, up
@section The viewport widget


@subsection Description

@subsection Signals

@subsection Functions

@deftypefun guint gtk_viewport_get_type (void)
@end deftypefun

@deftypefun GtkWidget* gtk_viewport_new (GtkAdjustment *@var{hadjustment}, GtkAdjustment *@var{vadjustment})
@end deftypefun

@deftypefun GtkAdjustment* gtk_viewport_get_hadjustment (GtkViewport *@var{viewport})
@end deftypefun

@deftypefun GtkAdjustment* gtk_viewport_get_vadjustment (GtkViewport *@var{viewport})
@end deftypefun

@deftypefun void gtk_viewport_set_hadjustment (GtkViewport *@var{viewport}, GtkAdjustment *@var{adjustment})
@end deftypefun

@deftypefun void gtk_viewport_set_vadjustment (GtkViewport *@var{viewport}, GtkAdjustment *@var{adjustment})
@end deftypefun

@deftypefun void gtk_viewport_set_shadow_type (GtkViewport *@var{viewport}, GtkShadowType @var{type})
@end deftypefun

@gtkstdmacros{Viewport, VIEWPORT}


@page
@node GtkVRuler, GtkVScale, GtkViewport, Widgets
@comment node-name, next, previous, up
@section The vertical ruler widget


@subsection Description

@subsection Signals

@subsection Functions

@deftypefun guint gtk_vruler_get_type (void)
@end deftypefun

@deftypefun GtkWidget* gtk_vruler_new (void)
@end deftypefun

@gtkstdmacros{VRuler, VRULER}


@page
@node GtkVScale, GtkVScrollbar, GtkVRuler, Widgets
@comment node-name, next, previous, up
@section The vertical ruler widget


@subsection Description

@subsection Signals

@subsection Functions

@deftypefun guint gtk_vscale_get_type (void)
@end deftypefun

@deftypefun GtkWidget* gtk_vscale_new (GtkAdjustment *@var{adjustment})
@end deftypefun

@gtkstdmacros{VScale, VSCALE}


@page
@node GtkVScrollbar, GtkVSeparator, GtkVScale, Widgets
@comment node-name, next, previous, up
@section The vertical scrollbar widget


@subsection Description

@subsection Signals

@subsection Functions

@deftypefun guint gtk_vscrollbar_get_type (void)
@end deftypefun

@deftypefun GtkWidget* gtk_vscrollbar_new (GtkAdjustment *@var{adjustment})
@end deftypefun

@gtkstdmacros{VScrollbar, VSCROLLBAR}


@page
@node GtkVSeparator, GtkWidget, GtkVScrollbar, Widgets
@comment node-name, next, previous, up
@section The vertical separator widget


@subsection Description

@subsection Signals

@subsection Functions

@deftypefun guint gtk_vseparator_get_type (void)
@end deftypefun

@deftypefun GtkWidget* gtk_vseparator_new (void)
@end deftypefun

@gtkstdmacros{VSeparator, VSEPARATOR}


@page
@node GtkWidget, GtkWindow, GtkVSeparator, Widgets
@comment node-name, next, previous, up
@section The base widget


@subsection Description

@subsection Signals

@deftypefn Signal void GtkWidget::show (GtkWidget *@var{widget})
@end deftypefn

@deftypefn Signal void GtkWidget::hide (GtkWidget *@var{widget})
@end deftypefn

@deftypefn Signal void GtkWidget::map (GtkWidget *@var{widget})
@end deftypefn

@deftypefn Signal void GtkWidget::unmap (GtkWidget *@var{widget})
@end deftypefn

@deftypefn Signal void GtkWidget::realize (GtkWidget *@var{widget})
@end deftypefn

@deftypefn Signal void GtkWidget::unrealize (GtkWidget *@var{widget})
@end deftypefn

@deftypefn Signal void GtkWidget::draw (GtkWidget *@var{widget}, GdkRectangle *@var{area})
@end deftypefn

@deftypefn Signal void GtkWidget::draw_focus (GtkWidget *@var{widget})
@end deftypefn

@deftypefn Signal void GtkWidget::draw_default (GtkWidget *@var{widget})
@end deftypefn

@deftypefn Signal void GtkWidget::size_request (GtkWidget *@var{widget}, GtkRequisition *@var{requisition})
@end deftypefn

@deftypefn Signal void GtkWidget::size_allocate (GtkWidget *@var{widget}, GtkAllocation *@var{allocation})
@end deftypefn

@deftypefn Signal void GtkWidget::state_changed (GtkWidget *@var{widget})
@end deftypefn

@deftypefn Signal gint GtkWidget::install_accelerator (GtkWidget *@var{widget}, gchar *@var{signal_name}, gchar @var{key}, guint8 @var{modifiers})
@end deftypefn

@deftypefn Signal void GtkWidget::remove_accelerator (GtkWidget *@var{widget}, gchar *@var{signal_name})
@end deftypefn

@deftypefn Signal gint GtkWidget::event (GtkWidget *@var{widget}, GdkEvent *@var{event})
@end deftypefn

@deftypefn Signal gint GtkWidget::button_press_event (GtkWidget *@var{widget}, GdkEventButton *@var{event})
@end deftypefn

@deftypefn Signal gint GtkWidget::button_release_event (GtkWidget *@var{widget}, GdkEventButton *@var{event})
@end deftypefn

@deftypefn Signal gint GtkWidget::motion_notify_event (GtkWidget *@var{widget}, GdkEventMotion *@var{event})
@end deftypefn

@deftypefn Signal gint GtkWidget::delete_event (GtkWidget *@var{widget}, GdkEventAny *@var{event})
@end deftypefn

@deftypefn Signal gint GtkWidget::destroy_event (GtkWidget *@var{widget}, GdkEventAny *@var{event})
@end deftypefn

@deftypefn Signal gint GtkWidget::expose_event (GtkWidget *@var{widget}, GdkEventExpose *@var{event})
@end deftypefn

@deftypefn Signal gint GtkWidget::key_press_event (GtkWidget *@var{widget}, GdkEventKey *@var{event})
@end deftypefn

@deftypefn Signal gint GtkWidget::key_release_event (GtkWidget *@var{widget}, GdkEventKey *@var{event})
@end deftypefn

@deftypefn Signal gint GtkWidget::enter_notify_event (GtkWidget *@var{widget}, GdkEventCrossing *@var{event})
@end deftypefn

@deftypefn Signal gint GtkWidget::leave_notify_event (GtkWidget *@var{widget}, GdkEventCrossing *@var{event})
@end deftypefn

@deftypefn Signal gint GtkWidget::configure_event (GtkWidget *@var{widget}, GdkEventConfigure *@var{event})
@end deftypefn

@deftypefn Signal gint GtkWidget::focus_in_event (GtkWidget *@var{widget}, GdkEventFocus *@var{event})
@end deftypefn

@deftypefn Signal gint GtkWidget::focus_out_event (GtkWidget *@var{widget}, GdkEventFocus *@var{event})
@end deftypefn

@deftypefn Signal gint GtkWidget::map_event (GtkWidget *@var{widget}, GdkEventAny *@var{event})
@end deftypefn

@deftypefn Signal gint GtkWidget::unmap_event (GtkWidget *@var{widget}, GdkEventAny *@var{event})
@end deftypefn

@deftypefn Signal gint GtkWidget::property_notify_event (GtkWidget *@var{widget}, GdkEventProperty *@var{event})
@end deftypefn

@deftypefn Signal gint GtkWidget::selection_clear_event (GtkWidget *@var{widget}, GdkEventSelection *@var{event})
@end deftypefn

@deftypefn Signal gint GtkWidget::selection_request_event (GtkWidget *@var{widget}, GdkEventSelection *@var{event})
@end deftypefn

@deftypefn Signal gint GtkWidget::selection_notify_event (GtkWidget *@var{widget}, GdkEventSelection *@var{event})
@end deftypefn

@deftypefn Signal gint GtkWidget::drop_event (GtkWidget *@var{widget}, GdkEventDrop *@var{event})
@end deftypefn

@deftypefn Signal gint GtkWidget::drag_begin_event (GtkWidget *@var{widget}, GdkEventDragBegin *@var{event})
@end deftypefn

@deftypefn Signal gint GtkWidget::other_event (GtkWidget *@var{widget}, GdkEventOther *@var{event})
@end deftypefn

@subsection Functions

@deftypefun guint gtk_widget_get_type (void)
@end deftypefun

@deftypefun void gtk_widget_class_init (GtkWidgetClass *@var{class})
@end deftypefun

@deftypefun void gtk_widget_init (GtkWidget *@var{widget})
@end deftypefun

@deftypefun void gtk_widget_destroy (GtkWidget *@var{widget})
@end deftypefun

@deftypefun void gtk_widget_show (GtkWidget *@var{widget})
@end deftypefun

@deftypefun void gtk_widget_hide (GtkWidget *@var{widget})
@end deftypefun

@deftypefun void gtk_widget_map (GtkWidget *@var{widget})
@end deftypefun

@deftypefun void gtk_widget_unmap (GtkWidget *@var{widget})
@end deftypefun

@deftypefun void gtk_widget_realize (GtkWidget *@var{widget})
@end deftypefun

@deftypefun void gtk_widget_unrealize (GtkWidget *@var{widget})
@end deftypefun

@deftypefun void gtk_widget_draw (GtkWidget *@var{widget}, GdkRectangle *@var{area})
@end deftypefun

@deftypefun void gtk_widget_draw_focus (GtkWidget *@var{widget})
@end deftypefun

@deftypefun void gtk_widget_draw_children (GtkWidget *@var{widget})
@end deftypefun

@deftypefun void gtk_widget_size_request (GtkWidget *@var{widget}, GtkRequisition *@var{requisition})
@end deftypefun

@deftypefun void gtk_widget_size_allocate (GtkWidget *@var{widget}, GtkAllocation *@var{allocation})
@end deftypefun

@deftypefun void gtk_widget_install_accelerator (GtkWidget *@var{widget}, GtkAcceleratorTable *@var{table}, gchar *@var{signal_name}, gchar @var{key}, guint8 @var{modifiers})
@end deftypefun

@deftypefun void gtk_widget_remove_accelerator (GtkWidget *@var{widget}, GtkAcceleratorTable *@var{table}, gchar *@var{signal_name})
@end deftypefun

@deftypefun gint gtk_widget_event (GtkWidget *@var{widget}, GdkEvent *@var{event})
@end deftypefun

@deftypefun void gtk_widget_reparent (GtkWidget *@var{widget}, GtkWidget *@var{new_parent})
@end deftypefun

@deftypefun void gtk_widget_popup (GtkWidget *@var{widget}, gint @var{x}, gint @var{y})
@end deftypefun

@deftypefun gint gtk_widget_intersect (GtkWidget *@var{widget}, GdkRectangle *@var{area}, GdkRectangle *@var{intersection})
@end deftypefun

@deftypefun void gtk_widget_grab_focus (GtkWidget *@var{widget})
@end deftypefun

@deftypefun void gtk_widget_grab_default (GtkWidget *@var{widget})
@end deftypefun

@deftypefun void gtk_widget_restore_state (GtkWidget *@var{widget})
@end deftypefun

@deftypefun void gtk_widget_set_name (GtkWidget *@var{widget}, gchar *@var{name})
@end deftypefun

@deftypefun void gtk_widget_set_state (GtkWidget *@var{widget}, GtkStateType @var{state})
@end deftypefun

@deftypefun void gtk_widget_set_sensitive (GtkWidget *@var{widget}, gint sensitive)
@end deftypefun

@deftypefun void gtk_widget_set_parent (GtkWidget *@var{widget}, GtkWidget *@var{parent})
@end deftypefun

@deftypefun void gtk_widget_set_style (GtkWidget *@var{widget}, GtkStyle *@var{style})
@end deftypefun

@deftypefun void gtk_widget_set_uposition (GtkWidget *@var{widget}, gint @var{x}, gint @var{y})
@end deftypefun

@deftypefun void gtk_widget_set_usize (GtkWidget *@var{widget}, gint @var{width}, gint @var{height})
@end deftypefun

@deftypefun GtkWidget* gtk_widget_get_toplevel (GtkWidget *@var{widget})
@end deftypefun

@deftypefun GtkWidget* gtk_widget_get_ancestor (GtkWidget *@var{widget}, gint @var{type})
@end deftypefun

@deftypefun GdkColormap* gtk_widget_get_colormap (GtkWidget *@var{widget})
@end deftypefun

@deftypefun GdkVisual* gtk_widget_get_visual (GtkWidget *@var{visual})
@end deftypefun

@deftypefun GtkStyle* gtk_widget_get_style (GtkWidget *@var{style})
@end deftypefun

@gtkstdmacros{Widget, WIDGET}


@page
@node GtkWindow, , GtkWidget, Widgets
@comment node-name, next, previous, up
@section The window widget


@subsection Description

@subsection Signals

@deftypefn Signal void GtkWindow::move_resize (GtkWindow *@var{window}, gint *@var{x}, gint *@var{y}, gint @var{width}, gint @var{height})
@end deftypefn

@subsection Functions

@deftypefun guint gtk_window_get_type (void)
@end deftypefun

@deftypefun GtkWidget* gtk_window_new (GtkWindowType @var{type})
@end deftypefun

@deftypefun void gtk_window_set_title (GtkWindow *@var{window}, gchar *@var{title})
@end deftypefun

@deftypefun void gtk_window_set_focus (GtkWindow *@var{window}, GtkWidget *@var{focus})
@end deftypefun

@deftypefun void gtk_window_set_default (GtkWindow *@var{window}, GtkWidget *@var{defaultw})
@end deftypefun

@deftypefun void gtk_window_set_policy (GtkWindow *@var{window}, gint @var{allow_shrink}, gint @var{allow_grow}, gint @var{auto_shrink})
@end deftypefun

@deftypefun void gtk_window_add_accelerator_table (GtkWindow *@var{window}, GtkAcceleratorTable *@var{table})
@end deftypefun

@deftypefun void gtk_window_remove_accelerator_table (GtkWindow *@var{window}, GtkAcceleratorTable *@var{table})
@end deftypefun

@deftypefun void gtk_window_position (GtkWindow *@var{window}, GtkWindowPosition @var{position})
@end deftypefun

@gtkstdmacros{Window, WINDOW}


@node Other Objects, Miscellaneous, Widgets, Top
@comment node-name, next, previous, up
@chapter Utility objects


@menu
* GtkAdjustment::               The adjustment object.
* GtkData::                     The data object.
@end menu


@node GtkAdjustment, GtkData, Other Objects, Other Objects
@comment node-name, next, previous, up
@section The adjustment object


@node GtkData, , GtkAdjustment, Other Objects
@comment node-name, next, previous, up
@section The data object


@node Miscellaneous, Examples, Other Objects, Top
@comment node-name, next, previous, up
@chapter Initialization, exit and other features


@menu
* Initialization and exit::     Initializing and exiting GTK.
* Menu Factories::              Simplified menu creation.
* Tree Factories::              Simplified tree creation.
* Tool Tips::                   Pop up help mechanism.
* Resource Files::              Resource files.
* Standard Macros::             Macros defined by all objects.
@end menu


@node Initialization and exit, Menu Factories, Miscellaneous, Miscellaneous
@comment node-name, next, previous, up
@section Initializing and exiting GTK


@node Menu Factories, Tree Factories, Initialization and exit, Miscellaneous
@comment node-name, next, previous, up
@section Simplified menu creation


@node Tree Factories, Tool Tips, Menu Factories, Miscellaneous
@comment node-name, next, previous, up
@section Simplified tree creation


@node Tool Tips, Resource Files, Tree Factories, Miscellaneous
@comment node-name, next, previous, up
@section Pop up help mechanism


@node Resource Files, Standard Macros, Tool Tips, Miscellaneous
@comment node-name, next, previous, up
@section Pop up help mechanism


@node Standard Macros, , Resource Files, Miscellaneous
@comment node-name, next, previous, up
@section Macros defined by all objects

There are three macros that are defined by all object types. The first
two are used for performing casts and the last is for querying whether
an object is of a particular type. These macros are both conveniences
and debugging tools. If the GTK library was compiled with @code{NDEBUG}
defined as a preprocessor symbol (via the -DNDEBUG to cc), then the
macros check the object type and emit a warning if the cast is
invalid. Doing such checking is fairly expensive since the cast macros
are used everywhere in GTK and would normally be turned off in a public
release of a product. Note: The functions below are indeed macros, but
they may be considered functions for most purposes.

@deftypefun Gtk<ObjectType>* GTK_<OBJECT_TYPE> (gpointer @var{obj})
Cast a generic pointer to @code{Gtk<ObjectType>*}. This function is
provided in order to be able to provide checking during development
stages of code development since it is possible to examine the actual
type of object (using @code{gtk_type_is_a}) before performing the cast.
@end deftypefun

@deftypefun Gtk<ObjectType>Class* GTK_<OBJECT_TYPE>_CLASS (gpointer @var{class})
Cast a generic pointer to @code{Gtk<ObjectType>Class*}. Like
@code{GTK_<ObjectType>}, this function is, in reality, a macro.
@end deftypefun

@deftypefun gint GTK_IS_<ObjectType> (gpointer @var{obj})
Determine if a generic pointer refers to a @code{Gtk<ObjectType>}
object. This function is, in reality, a macro wrapper around the
@code{gtk_type_is_a} function (@pxref{Objects}).
@end deftypefun


@node Examples, Object Implementation, Miscellaneous, Top
@comment node-name, next, previous, up
@chapter Using GTK


@menu
* Simple::                      The simplest GTK program.
* Hello World::                 Hello world in GTK.
* Hello World II::              An enhanced hello world.
* Hello World III::             Making Hello World II robust.
@end menu


@node Simple, Hello World, Examples, Examples
@comment node-name, next, previous, up
@section The simplest GTK program


The 16 line GTK program shown below is just about the simplest possible
program which uses GTK. (Well, technically, you don't have to create the
window and it would still be a program which uses GTK). The program,
when compiled and run, will create a single window 200x200 pixels in
size. The program does not exit until its is explicitly killed using the
shell or a window manager function.

@example
#include <gtk/gtk.h>

int
main (int argc, char *argv[])
@{
  GtkWidget *window;

  gtk_init (&argc, &argv);

  window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
  gtk_widget_show (window);

  gtk_main ();

  return 0;
@}
@end example

The first point of interest in this program is the standard
initialization line.

@example
  gtk_init (&argc, &argv);
@end example

Almost every GTK program will contain such a line. GTK will initialize
itself and GDK and remove any command line arguments it recognizes from
@var{argc} and @var{argv}.

The next two lines of code create and display a window.

@example
  window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
  gtk_widget_show (window);
@end example

The @code{GTK_WINDOW_TOPLEVEL} argument specifies that we want the
window to undergo window manager decoration and placement. One might be
lead to think that the window, since it has no children, would be 0x0
pixels in size. But, this is not the case because a window that has no
children defaults to 200x200 pixels in size. Mainly because 0x0 windows
are annoying to manipulate or even see in some cases.

The last line enters the GTK main processing loop.

@example
  gtk_main ();
@end example

Normally, @code{gtk_main} is called once and the program should exit
when it returns. @xref{Initialization and exit}.


@node Hello World, Hello World II, Simple, Examples
@comment node-name, next, previous, up
@section Hello world in GTK


@example
#include <gtk/gtk.h>

int
main (int argc, char *argv[])
@{
  GtkWidget *window;
  GtkWidget *label;

  gtk_init (&argc, &argv);

  window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
  gtk_container_border_width (GTK_CONTAINER (window), 10);

  label = gtk_label_new ("Hello World");
  gtk_container_add (GTK_CONTAINER (window), label);
  gtk_widget_show (label);

  gtk_widget_show (window);

  gtk_main ();

  return 0;
@}
@end example


@node Hello World II, Hello World III, Hello World, Examples
@comment node-name, next, previous, up
@section An enhanced hello world


@example
#include "gtk.h"

void
hello (void)
@{
  g_print ("Hello World\n");
  gtk_exit (0);
@}

int
main (int argc, char *argv[])
@{
  GtkWidget *window;
  GtkWidget *button;

  gtk_init (&argc, &argv);

  window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
  gtk_container_border_width (GTK_CONTAINER (window), 10);

  button = gtk_button_new_with_label ("Hello World");
  gtk_signal_connect (GTK_OBJECT (button), "clicked",
		      GTK_SIGNAL_FUNC (hello), NULL);
  gtk_container_add (GTK_CONTAINER (window), button);
  gtk_widget_show (button);

  gtk_widget_show (window);

  gtk_main ();

  return 0;
@}
@end example


@node Hello World III, , Hello World II, Examples
@comment node-name, next, previous, up
@section Making Hello World II robust


@example
#include "gtk.h"

void
hello (void)
@{
  g_print ("Hello World\n");
  gtk_exit (0);
@}

void
destroy (void)
@{
  gtk_exit (0);
@}

int
main (int argc, char *argv[])
@{
  GtkWidget *window;
  GtkWidget *button;

  gtk_init (&argc, &argv);

  window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
  gtk_signal_connect (GTK_OBJECT (window), "destroy",
		      GTK_SIGNAL_FUNC (destroy), NULL);
  gtk_container_border_width (GTK_CONTAINER (window), 10);

  button = gtk_button_new_with_label ("Hello World");
  gtk_signal_connect (GTK_OBJECT (button), "clicked",
		      GTK_SIGNAL_FUNC (hello), NULL);
  gtk_signal_connect_object (GTK_OBJECT (button), "clicked",
			     GTK_SIGNAL_FUNC (gtk_widget_destroy),
			     GTK_OBJECT (window));
  gtk_container_add (GTK_CONTAINER (window), button);
  gtk_widget_show (button);

  gtk_widget_show (window);

  gtk_main ();

  return 0;
@}
@end example


@node Object Implementation, Signal Implementation, Examples, Top
@comment node-name, next, previous, up
@chapter Object internals
@cindex Object Implementaton

Objects (or the @code{GtkObject} type) and the class hierarchy in
general is implemented via a hierarchy of structs and type casting. Be
aware that when classes are mentioned it is the conceptual idea of
classes that is being referred to. GTK is written entirely in C which
provides no direct support for classes.

The first part to the class mechanism is the object fields. These are
fields that will be used on a per object basis. For example, the widget
type contains a field for the widgets parent. Every derived type needs a
reference to its parent type. A descendant class of @code{GtkObject}
would define itself like:

@example
struct Descendant
@{
  GtkObject object;

  @dots{}
@};
@end example

It is important to note that the @code{GtkObject} field needs to appear
first in the descendant type structure. This allows pointers to objects
of type @code{Descendant} to be cast to pointers to @code{GtkObjects}'s
and vice-versa.

The second part to the class mechanism is the class fields. These fields
are defined on a per class basis. In the case of widgets, the class
fields are all the ``virtual'' functions for widgets. The
@code{GtkObject} class defines the @code{destroy} virtual function and
the necessary fields for the signal mechanism as well as a field for
determining the runtime type of an object. A virtual function is
semantically the same as it is in C++. That is, the actual function that
is called is determined based on the type of the object. Or, more
specifically, the actual function call depends on the class structure
that is pointed to by the @code{klass} field of the @code{GtkObject}
structure.

To see how the class fields work it is necessary to see the object
fields for a @code{GtkObject}. The @code{GtkObject} type is defined as
follows:

@example
typedef struct _GtkObject GtkObject;

struct _GtkObject
@{
  guint32 flags;
  GtkObjectClass *klass;
  gpointer object_data;
@};
@end example

The @code{class} field actually points to a class structure derived from
@code{GtkObjectClass}. By convention, each new type defines its own
class structure even if it is unnecessary. As an example, the
hypothetical @code{Descendant} class would define its class structure
as:

@example
struct DescendantClass
@{
  GtkObjectClass parent_class;

  @dots{}
@};
@end example

It is convention to name the parent class field (@code{GtkObjectClass}
in this case), @code{parent_class}. For the same reason as stated above
for the object structure, the parent class field must be the first field
in the class structure.

@strong{Note:} GTK assumes that the first field in a structure will be
placed by the compiler at the start of the structure. This is certainly
true for gcc, however, from my precursory reading of the C standard I
was unable to come to a definite conclusion as to whether this was
required or simply done for simplicity. I'm not too worried about this
assumption, though, as every C compiler I've ever encountered would work
with GTK.

The @code{flags} field of the @code{GtkObject} structure is used to keep
track of a relatively few object flags and is also used by the
@code{GtkWidget} type to store additional flags. At this time, the upper
16 bits of the flags field are reserved but unused.

The @code{object_data} field of the @code{GtkObject} structure is an
opaque pointer used by the object data mechanism. In truth, it is a
pointer to the beginning of the data list which is composed of the
following structures.

@example
typedef struct _GtkObjectData GtkObjectData;

struct _GtkObjectData
@{
  guint id;
  gpointer data;
  GtkObjectData *next;
@};
@end example

The data mechanism allows arbitrary data to be associated with a
character string key in any object. A hash table is used to transform
the character string key into the data id and then a search through the
list is made to see if the data exists. The assumption being that the
data list will usually be short and therefore a linear search is
ok. Future work on the data mechanism might make use of a resizable
array instead of a linked list. This would shrink the overhead of the
@code{GtkObjectData} structure by 4 bytes on 32 bit architectures.


@node Signal Implementation, Widget Implementation, Object Implementation, Top
@comment node-name, next, previous, up
@chapter Signal internals
@cindex Signal Implementation


@node Widget Implementation, Function Index, Signal Implementation, Top
@comment node-name, next, previous, up
@chapter Widget internals
@cindex Widget Implementation


@node Function Index, Concept Index, Widget Implementation, Top
@comment node-name, next, previous, up
@unnumbered Function Index

@printindex fn


@node Concept Index, , Function Index, Top
@comment node-name, next, previous, up
@unnumbered Concept Index

@printindex cp


@summarycontents
@contents
@bye