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Functions
Types and Values
#define | GTK_PRIORITY_HIGH |
#define | GTK_PRIORITY_INTERNAL |
#define | GTK_PRIORITY_DEFAULT |
#define | GTK_PRIORITY_LOW |
Description
Before using GTK+, you need to initialize it; initialization connects
to the window system display, and parses some standard command line
arguments. The gtk_init()
function initializes GTK+. gtk_init()
exits
the application if errors occur; to avoid this, use gtk_init_check()
.
gtk_init_check()
allows you to recover from a failed GTK+
initialization - you might start up your application in text mode instead.
Like all GUI toolkits, GTK+ uses an event-driven programming model. When the user is doing nothing, GTK+ sits in the main loop and waits for input. If the user performs some action - say, a mouse click - then the main loop "wakes up" and delivers an event to GTK+. GTK+ forwards the event to one or more widgets.
When widgets receive an event, they frequently emit one or more
signals. Signals notify your program that
"something interesting happened" by invoking functions you've
connected to the signal with g_signal_connect()
. Functions connected
to a signal are often termed callbacks.
When your callbacks are invoked, you would typically take some action - for example, when an Open button is clicked you might display a GtkFileSelectionDialog. After a callback finishes, GTK+ will return to the main loop and await more user input.
Example 2. Typical main
function for a GTK+ application
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int main (int argc, char **argv) { /* Initialize i18n support */ gtk_set_locale (); /* Initialize the widget set */ gtk_init (&argc, &argv); /* Create the main window */ mainwin = gtk_window_new (GTK_WINDOW_TOPLEVEL); /* Set up our GUI elements */ ... /* Show the application window */ gtk_widget_show_all (mainwin); /* Enter the main event loop, and wait for user interaction */ gtk_main (); /* The user lost interest */ return 0; } |
It's OK to use the GLib main loop directly instead of gtk_main()
,
though it involves slightly more typing. See GMainLoop in the GLib
documentation.
Functions
gtk_set_locale ()
gchar *
gtk_set_locale (void
);
gtk_set_locale
has been deprecated since version 2.24 and should not be used in newly-written code.
Use setlocale()
directly
Initializes internationalization support for GTK+. gtk_init()
automatically does this, so there is typically no point
in calling this function.
If you are calling this function because you changed the locale after GTK+ is was initialized, then calling this function may help a bit. (Note, however, that changing the locale after GTK+ is initialized may produce inconsistent results and is not really supported.)
In detail - sets the current locale according to the
program environment. This is the same as calling the C library function
setlocale (LC_ALL, "")
but also takes care of the
locale specific setup of the windowing system used by GDK.
Returns
a string corresponding to the locale set, typically in the
form lang_COUNTRY, where lang is an ISO-639 language code, and
COUNTRY is an ISO-3166 country code. On Unix, this form matches the
result of the setlocale()
; it is also used on other machines, such as
Windows, where the C library returns a different result. The string is
owned by GTK+ and should not be modified or freed.
gtk_disable_setlocale ()
void
gtk_disable_setlocale (void
);
gtk_disable_setlocale
is deprecated and should not be used in newly-written code.
Prevents gtk_init()
, gtk_init_check()
, gtk_init_with_args()
and
gtk_parse_args()
from automatically
calling setlocale (LC_ALL, "")
. You would
want to use this function if you wanted to set the locale for
your program to something other than the user's locale, or if
you wanted to set different values for different locale categories.
Most programs should not need to call this function.
gtk_get_default_language ()
PangoLanguage *
gtk_get_default_language (void
);
Returns the PangoLanguage for the default language currently in effect. (Note that this can change over the life of an application.) The default language is derived from the current locale. It determines, for example, whether GTK+ uses the right-to-left or left-to-right text direction.
This function is equivalent to pango_language_get_default()
. See
that function for details.
gtk_parse_args ()
gboolean gtk_parse_args (int *argc
,char ***argv
);
Parses command line arguments, and initializes global
attributes of GTK+, but does not actually open a connection
to a display. (See gdk_display_open()
, gdk_get_display_arg_name()
)
Any arguments used by GTK+ or GDK are removed from the array and
argc
and argv
are updated accordingly.
There is no need to call this function explicitely if you are using
gtk_init()
, or gtk_init_check()
.
gtk_init ()
void gtk_init (int *argc
,char ***argv
);
Call this function before using any other GTK+ functions in your GUI applications. It will initialize everything needed to operate the toolkit and parses some standard command line options.
argc
and argv
are adjusted accordingly so your own code will
never see those standard arguments.
Note that there are some alternative ways to initialize GTK+:
if you are calling gtk_parse_args()
, gtk_init_check()
,
gtk_init_with_args()
or g_option_context_parse()
with
the option group returned by gtk_get_option_group()
,
you don't have to call gtk_init()
.
This function will terminate your program if it was unable to
initialize the windowing system for some reason. If you want
your program to fall back to a textual interface you want to
call gtk_init_check()
instead.
Since 2.18, GTK+ calls signal (SIGPIPE, SIG_IGN)
during initialization, to ignore SIGPIPE signals, since these are
almost never wanted in graphical applications. If you do need to
handle SIGPIPE for some reason, reset the handler after gtk_init()
,
but notice that other libraries (e.g. libdbus or gvfs) might do
similar things.
gtk_init_check ()
gboolean gtk_init_check (int *argc
,char ***argv
);
This function does the same work as gtk_init()
with only
a single change: It does not terminate the program if the GUI can't be
initialized. Instead it returns FALSE
on failure.
This way the application can fall back to some other means of communication with the user - for example a curses or command line interface.
Parameters
argc |
Address of the |
[inout] |
argv |
Address of the |
[array length=argc][inout][allow-none] |
gtk_init_with_args ()
gboolean gtk_init_with_args (int *argc
,char ***argv
,const char *parameter_string
,GOptionEntry *entries
,const char *translation_domain
,GError **error
);
This function does the same work as gtk_init_check()
.
Additionally, it allows you to add your own commandline options,
and it automatically generates nicely formatted
--help
output. Note that your program will
be terminated after writing out the help output.
Parameters
argc |
a pointer to the number of command line arguments. |
|
argv |
a pointer to the array of command line arguments. |
[inout][array length=argc] |
parameter_string |
a string which is displayed in
the first line of |
|
entries |
a |
[array zero-terminated=1] |
translation_domain |
a translation domain to use for translating
the |
|
error |
a return location for errors |
Since 2.6
gtk_get_option_group ()
GOptionGroup *
gtk_get_option_group (gboolean open_default_display
);
Returns a GOptionGroup for the commandline arguments recognized
by GTK+ and GDK. You should add this group to your GOptionContext
with g_option_context_add_group()
, if you are using
g_option_context_parse()
to parse your commandline arguments.
Parameters
open_default_display |
whether to open the default display when parsing the commandline arguments |
Since 2.6
gtk_exit ()
void
gtk_exit (gint error_code
);
gtk_exit
is deprecated and should not be used in newly-written code.
Use the standard exit()
function instead.
Terminates the program and returns the given exit code to the caller. This function will shut down the GUI and free all resources allocated for GTK+.
gtk_events_pending ()
gboolean
gtk_events_pending (void
);
Checks if any events are pending. This can be used to update the GUI and invoke timeouts etc. while doing some time intensive computation.
Example 3. Updating the GUI during a long computation.
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/* computation going on */ ... while (gtk_events_pending ()) gtk_main_iteration (); ... /* computation continued */ |
gtk_main ()
void
gtk_main (void
);
Runs the main loop until gtk_main_quit()
is called. You can nest calls to
gtk_main()
. In that case gtk_main_quit()
will make the innermost invocation
of the main loop return.
gtk_main_level ()
guint
gtk_main_level (void
);
Asks for the current nesting level of the main loop. This can be useful
when calling gtk_quit_add()
.
gtk_main_quit ()
void
gtk_main_quit (void
);
Makes the innermost invocation of the main loop return when it regains control.
gtk_main_iteration ()
gboolean
gtk_main_iteration (void
);
Runs a single iteration of the mainloop. If no events are waiting to be
processed GTK+ will block until the next event is noticed. If you don't
want to block look at gtk_main_iteration_do()
or check if any events are
pending with gtk_events_pending()
first.
gtk_main_iteration_do ()
gboolean
gtk_main_iteration_do (gboolean blocking
);
Runs a single iteration of the mainloop. If no events are available either
return or block dependent on the value of blocking
.
gtk_main_do_event ()
void
gtk_main_do_event (GdkEvent *event
);
Processes a single GDK event. This is public only to allow filtering of events between GDK and GTK+. You will not usually need to call this function directly.
While you should not call this function directly, you might want to know how exactly events are handled. So here is what this function does with the event:
Compress enter/leave notify events. If the event passed build an enter/leave pair together with the next event (peeked from GDK) both events are thrown away. This is to avoid a backlog of (de-)highlighting widgets crossed by the pointer.
Find the widget which got the event. If the widget can't be determined the event is thrown away unless it belongs to a INCR transaction. In that case it is passed to
gtk_selection_incr_event()
.Then the event is passed on a stack so you can query the currently handled event with
gtk_get_current_event()
.-
The event is sent to a widget. If a grab is active all events for widgets that are not in the contained in the grab widget are sent to the latter with a few exceptions:
Deletion and destruction events are still sent to the event widget for obvious reasons.
Events which directly relate to the visual representation of the event widget.
Leave events are delivered to the event widget if there was an enter event delivered to it before without the paired leave event.
Drag events are not redirected because it is unclear what the semantics of that would be.
Another point of interest might be that all key events are first passed through the key snooper functions if there are any. Read the description of
gtk_key_snooper_install()
if you need this feature. After finishing the delivery the event is popped from the event stack.
GtkModuleInitFunc ()
void (*GtkModuleInitFunc) (gint *argc
,gchar ***argv
);
Each GTK+ module must have a function gtk_module_init()
with this prototype.
This function is called after loading the module with the argc
and argv
cleaned from any arguments that GTK+ handles itself.
Parameters
argc |
Pointer to the number of arguments remaining after |
|
argv |
Points to the argument vector. |
gtk_true ()
gboolean
gtk_true (void
);
All this function does it to return TRUE
. This can be useful for example
if you want to inhibit the deletion of a window. Of course you should
not do this as the user expects a reaction from clicking the close
icon of the window...
Example 4. A persistent window
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##include <gtk/gtk.h> int main (int argc, char **argv) { GtkWidget *win, *but; gtk_init( &argc, &argv ); win = gtk_window_new (GTK_WINDOW_TOPLEVEL); g_signal_connect (win, "delete-event", G_CALLBACK (gtk_true), NULL); g_signal_connect (win, "destroy", G_CALLBACK (gtk_main_quit), NULL); but = gtk_button_new_with_label ("Close yourself. I mean it!"); g_signal_connect_swapped (but, "clicked", G_CALLBACK (gtk_object_destroy), win); gtk_container_add (GTK_CONTAINER (win), but); gtk_widget_show_all (win); gtk_main (); return 0; } |
gtk_false ()
gboolean
gtk_false (void
);
Analogical to gtk_true()
this function does nothing
but always returns FALSE
.
gtk_grab_add ()
void
gtk_grab_add (GtkWidget *widget
);
Makes widget
the current grabbed widget. This means that interaction with
other widgets in the same application is blocked and mouse as well as
keyboard events are delivered to this widget.
If widget
is not sensitive, it is not set as the current grabbed
widget and this function does nothing.
gtk_grab_get_current ()
GtkWidget *
gtk_grab_get_current (void
);
Queries the current grab of the default window group.
Queries the current grab of the default window group.
gtk_grab_remove ()
void
gtk_grab_remove (GtkWidget *widget
);
Removes the grab from the given widget. You have to pair calls to gtk_grab_add()
and gtk_grab_remove()
.
If widget
does not have the grab, this function does nothing.
gtk_init_add ()
void gtk_init_add (GtkFunction function
,gpointer data
);
gtk_init_add
is deprecated and should not be used in newly-written code.
This function is going to be removed in GTK+ 3.0
Registers a function to be called when the mainloop is started.
Parameters
function |
Function to invoke when |
|
data |
Data to pass to that function. |
gtk_quit_add_destroy ()
void gtk_quit_add_destroy (guint main_level
,GtkObject *object
);
gtk_quit_add_destroy
is deprecated and should not be used in newly-written code.
This function is going to be removed in GTK+ 3.0
Trigger destruction of object
in case the mainloop at level main_level
is quit.
gtk_quit_add ()
guint gtk_quit_add (guint main_level
,GtkFunction function
,gpointer data
);
gtk_quit_add
is deprecated and should not be used in newly-written code.
This function is going to be removed in GTK+ 3.0
Registers a function to be called when an instance of the mainloop is left.
Parameters
main_level |
Level at which termination the function shall be called. You can pass 0 here to have the function run at the termination of the current mainloop. |
|
function |
The function to call. This should return 0 to be removed from the list of quit handlers. Otherwise the function might be called again. |
|
data |
Pointer to pass when calling |
Returns
A handle for this quit handler (you need this for gtk_quit_remove()
)
or 0 if you passed a NULL
pointer in function
.
gtk_quit_add_full ()
guint gtk_quit_add_full (guint main_level
,GtkFunction function
,GtkCallbackMarshal marshal
,gpointer data
,GDestroyNotify destroy
);
gtk_quit_add_full
is deprecated and should not be used in newly-written code.
This function is going to be removed in GTK+ 3.0
Registers a function to be called when an instance of the mainloop is left.
In comparison to gtk_quit_add()
this function adds the possibility to
pass a marshaller and a function to be called when the quit handler is freed.
The former can be used to run interpreted code instead of a compiled function
while the latter can be used to free the information stored in data
(while
you can do this in function
as well)... So this function will mostly be
used by GTK+ wrappers for languages other than C.
Parameters
main_level |
Level at which termination the function shall be called. You can pass 0 here to have the function run at the termination of the current mainloop. |
|
function |
The function to call. This should return 0 to be removed from the list of quit handlers. Otherwise the function might be called again. |
|
marshal |
The marshaller to be used. If this is non- |
|
data |
Pointer to pass when calling |
|
destroy |
Function to call to destruct |
Returns
A handle for this quit handler (you need this for gtk_quit_remove()
)
or 0 if you passed a NULL
pointer in function
.
gtk_quit_remove ()
void
gtk_quit_remove (guint quit_handler_id
);
gtk_quit_remove
is deprecated and should not be used in newly-written code.
This function is going to be removed in GTK+ 3.0
Removes a quit handler by its identifier.
gtk_quit_remove_by_data ()
void
gtk_quit_remove_by_data (gpointer data
);
gtk_quit_remove_by_data
is deprecated and should not be used in newly-written code.
This function is going to be removed in GTK+ 3.0
Removes a quit handler identified by its data
field.
gtk_timeout_add_full ()
guint gtk_timeout_add_full (guint32 interval
,GtkFunction function
,GtkCallbackMarshal marshal
,gpointer data
,GDestroyNotify destroy
);
gtk_timeout_add_full
has been deprecated since version 2.4 and should not be used in newly-written code.
Use g_timeout_add_full()
instead.
Registers a function to be called periodically. The function will be called
repeatedly after interval
milliseconds until it returns FALSE
at which
point the timeout is destroyed and will not be called again.
Parameters
interval |
The time between calls to the function, in milliseconds (1/1000ths of a second.) |
|
function |
The function to call periodically. |
|
marshal |
The marshaller to use instead of the function (if non- |
|
data |
The data to pass to the function. |
|
destroy |
Function to call when the timeout is destroyed or |
gtk_timeout_add ()
guint gtk_timeout_add (guint32 interval
,GtkFunction function
,gpointer data
);
gtk_timeout_add
has been deprecated since version 2.4 and should not be used in newly-written code.
Use g_timeout_add()
instead.
Registers a function to be called periodically. The function will be called
repeatedly after interval
milliseconds until it returns FALSE
at which
point the timeout is destroyed and will not be called again.
gtk_timeout_remove ()
void
gtk_timeout_remove (guint timeout_handler_id
);
gtk_timeout_remove
has been deprecated since version 2.4 and should not be used in newly-written code.
Use g_source_remove()
instead.
Removes the given timeout destroying all information about it.
gtk_idle_add ()
guint gtk_idle_add (GtkFunction function
,gpointer data
);
gtk_idle_add
has been deprecated since version 2.4 and should not be used in newly-written code.
Use g_idle_add()
instead.
Causes the mainloop to call the given function whenever no events with
higher priority are to be processed. The default priority is
GTK_PRIORITY_DEFAULT
, which is rather low.
gtk_idle_add_priority ()
guint gtk_idle_add_priority (gint priority
,GtkFunction function
,gpointer data
);
gtk_idle_add_priority
has been deprecated since version 2.4 and should not be used in newly-written code.
Use g_idle_add_full()
instead.
Like gtk_idle_add()
this function allows you to have a function called
when the event loop is idle. The difference is that you can give a
priority different from GTK_PRIORITY_DEFAULT
to the idle function.
Parameters
priority |
The priority which should not be above |
|
function |
The function to call. |
|
data |
Data to pass to that function. |
gtk_idle_add_full ()
guint gtk_idle_add_full (gint priority
,GtkFunction function
,GtkCallbackMarshal marshal
,gpointer data
,GDestroyNotify destroy
);
gtk_idle_add_full
has been deprecated since version 2.4 and should not be used in newly-written code.
Use g_idle_add_full()
instead.
Like gtk_idle_add()
this function allows you to have a function called
when the event loop is idle. The difference is that you can give a
priority different from GTK_PRIORITY_DEFAULT
to the idle function.
Parameters
priority |
The priority which should not be above |
|
function |
The function to call. |
|
marshal |
The marshaller to use instead of the function (if non- |
|
data |
Data to pass to that function. |
|
destroy |
Function to call when the timeout is destroyed or |
gtk_idle_remove ()
void
gtk_idle_remove (guint idle_handler_id
);
gtk_idle_remove
has been deprecated since version 2.4 and should not be used in newly-written code.
Use g_source_remove()
instead.
Removes the idle function with the given id.
gtk_idle_remove_by_data ()
void
gtk_idle_remove_by_data (gpointer data
);
gtk_idle_remove_by_data
has been deprecated since version 2.4 and should not be used in newly-written code.
Use g_idle_remove_by_data()
instead.
Removes the idle function identified by the user data.
gtk_input_add_full ()
guint gtk_input_add_full (gint source
,GdkInputCondition condition
,GdkInputFunction function
,GtkCallbackMarshal marshal
,gpointer data
,GDestroyNotify destroy
);
gtk_input_add_full
has been deprecated since version 2.4 and should not be used in newly-written code.
Use g_io_add_watch_full()
instead.
Registers a function to be called when a condition becomes true on a file descriptor.
gtk_input_remove ()
void
gtk_input_remove (guint input_handler_id
);
gtk_input_remove
has been deprecated since version 2.4 and should not be used in newly-written code.
Use g_source_remove()
instead.
Removes the function with the given id.
GTK_PRIORITY_REDRAW
#define GTK_PRIORITY_REDRAW (G_PRIORITY_HIGH_IDLE + 20)
GTK_PRIORITY_REDRAW
has been deprecated since version 2.4 and should not be used in newly-written code.
This macro is deprecated. You should use GDK_PRIORITY_REDRAW
instead.
Use this priority for redrawing related stuff. It is used internally by
GTK+ to do pending redraws. This priority is lower than GTK_PRIORITY_RESIZE
to avoid redrawing a widget just before resizing (and therefore redrawing
it again).
GTK_PRIORITY_RESIZE
#define GTK_PRIORITY_RESIZE (G_PRIORITY_HIGH_IDLE + 10)
Use this priority for resizing related stuff. It is used internally by
GTK+ to compute the sizes of widgets. This priority is higher than
GTK_PRIORITY_REDRAW
to avoid resizing a widget which was just redrawn.
gtk_key_snooper_install ()
guint gtk_key_snooper_install (GtkKeySnoopFunc snooper
,gpointer func_data
);
gtk_key_snooper_install
is deprecated and should not be used in newly-written code.
Installs a key snooper function, which will get called on all key events before delivering them normally.
GtkKeySnoopFunc ()
gint (*GtkKeySnoopFunc) (GtkWidget *grab_widget
,GdkEventKey *event
,gpointer func_data
);
GtkKeySnoopFunc
is deprecated and should not be used in newly-written code.
Key snooper functions are called before normal event delivery. They can be used to implement custom key event handling.
Parameters
grab_widget |
the widget to which the event will be delivered. |
|
event |
the key event. |
|
func_data |
the |
gtk_key_snooper_remove ()
void
gtk_key_snooper_remove (guint snooper_handler_id
);
Removes the key snooper function with the given id.
gtk_get_current_event ()
GdkEvent *
gtk_get_current_event (void
);
Obtains a copy of the event currently being processed by GTK+. For
example, if you get a "clicked" signal from GtkButton, the current
event will be the GdkEventButton that triggered the "clicked"
signal. The returned event must be freed with gdk_event_free()
.
If there is no current event, the function returns NULL
.
gtk_get_current_event_time ()
guint32
gtk_get_current_event_time (void
);
If there is a current event and it has a timestamp, return that
timestamp, otherwise return GDK_CURRENT_TIME
.
gtk_get_current_event_state ()
gboolean
gtk_get_current_event_state (GdkModifierType *state
);
If there is a current event and it has a state field, place
that state field in state
and return TRUE
, otherwise return
FALSE
.
gtk_get_event_widget ()
GtkWidget *
gtk_get_event_widget (GdkEvent *event
);
If event
is NULL
or the event was not associated with any widget,
returns NULL
, otherwise returns the widget that received the event
originally.
gtk_propagate_event ()
void gtk_propagate_event (GtkWidget *widget
,GdkEvent *event
);
Sends an event to a widget, propagating the event to parent widgets
if the event remains unhandled. Events received by GTK+ from GDK
normally begin in gtk_main_do_event()
. Depending on the type of
event, existence of modal dialogs, grabs, etc., the event may be
propagated; if so, this function is used. gtk_propagate_event()
calls gtk_widget_event()
on each widget it decides to send the
event to. So gtk_widget_event()
is the lowest-level function; it
simply emits the "event" and possibly an event-specific signal on a
widget. gtk_propagate_event()
is a bit higher-level, and
gtk_main_do_event()
is the highest level.
All that said, you most likely don't want to use any of these
functions; synthesizing events is rarely needed. Consider asking on
the mailing list for better ways to achieve your goals. For
example, use gdk_window_invalidate_rect()
or
gtk_widget_queue_draw()
instead of making up expose events.
Types and Values
GTK_PRIORITY_HIGH
#define GTK_PRIORITY_HIGH G_PRIORITY_HIGH
GTK_PRIORITY_HIGH
has been deprecated since version 2.4 and should not be used in newly-written code.
This macro is deprecated. You should use G_PRIORITY_HIGH
instead.
Use this for high priority timeouts. This priority is never used inside GTK+ so everything running at this priority will be running before anything inside the toolkit.
GTK_PRIORITY_INTERNAL
#define GTK_PRIORITY_INTERNAL GTK_PRIORITY_REDRAW
GTK_PRIORITY_INTERNAL
is deprecated and should not be used in newly-written code.
This priority is for GTK+ internal stuff. Don't use it in your applications.
GTK_PRIORITY_DEFAULT
#define GTK_PRIORITY_DEFAULT G_PRIORITY_DEFAULT_IDLE
GTK_PRIORITY_DEFAULT
has been deprecated since version 2.4 and should not be used in newly-written code.
This macro is deprecated. You should use G_PRIORITY_DEFAULT_IDLE
instead.
Default priority for idle functions.
GTK_PRIORITY_LOW
#define GTK_PRIORITY_LOW G_PRIORITY_LOW
GTK_PRIORITY_LOW
has been deprecated since version 2.4 and should not be used in newly-written code.
This macro is deprecated. You should use G_PRIORITY_LOW
instead.
Priority for very unimportant background tasks.
See Also
See the GLib manual, especially GMainLoop and signal-related
functions such as g_signal_connect()
.