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General

General — Library initialization and miscellaneous functions

Includes

#include <gdk/gdk.h>

Description

This section describes the GDK initialization functions and miscellaneous utility functions, as well as deprecation facilities.

The GDK and GTK+ headers annotate deprecated APIs in a way that produces compiler warnings if these deprecated APIs are used. The warnings can be turned off by defining the macro GDK_DISABLE_DEPRECATION_WARNINGS before including the glib.h header.

GDK and GTK+ also provide support for building applications against defined subsets of deprecated or new APIs. Define the macro GDK_VERSION_MIN_REQUIRED to specify up to what version you want to receive warnings about deprecated APIs. Define the macro GDK_VERSION_MAX_ALLOWED to specify the newest version whose API you want to use.

Functions

gdk_init ()

void
gdk_init (gint *argc,
          gchar ***argv);

Initializes the GDK library and connects to the windowing system. If initialization fails, a warning message is output and the application terminates with a call to exit(1).

Any arguments used by GDK are removed from the array and argc and argv are updated accordingly.

GTK+ initializes GDK in gtk_init() and so this function is not usually needed by GTK+ applications.

Parameters

argc

the number of command line arguments.

[inout]

argv

the array of command line arguments.

[array length=argc][inout]

gdk_init_check ()

gboolean
gdk_init_check (gint *argc,
                gchar ***argv);

Initializes the GDK library and connects to the windowing system, returning TRUE on success.

Any arguments used by GDK are removed from the array and argc and argv are updated accordingly.

GTK+ initializes GDK in gtk_init() and so this function is not usually needed by GTK+ applications.

Parameters

argc

the number of command line arguments.

[inout]

argv

the array of command line arguments.

[array length=argc][inout]

Returns

TRUE if initialization succeeded.


gdk_parse_args ()

void
gdk_parse_args (gint *argc,
                gchar ***argv);

Parse command line arguments, and store for future use by calls to gdk_display_open().

Any arguments used by GDK are removed from the array and argc and argv are updated accordingly.

You shouldn’t call this function explicitly if you are using gtk_init(), gtk_init_check(), gdk_init(), or gdk_init_check().

Parameters

argc

the number of command line arguments.

 

argv

the array of command line arguments.

[inout][array length=argc]

Since: 2.2


gdk_get_display_arg_name ()

const gchar *
gdk_get_display_arg_name (void);

Gets the display name specified in the command line arguments passed to gdk_init() or gdk_parse_args(), if any.

Returns

the display name, if specified explicitly, otherwise NULL this string is owned by GTK+ and must not be modified or freed.

[nullable]

Since: 2.2


gdk_notify_startup_complete ()

void
gdk_notify_startup_complete (void);

Indicates to the GUI environment that the application has finished loading. If the applications opens windows, this function is normally called after opening the application’s initial set of windows.

GTK+ will call this function automatically after opening the first GtkWindow unless gtk_window_set_auto_startup_notification() is called to disable that feature.

Since: 2.2


gdk_notify_startup_complete_with_id ()

void
gdk_notify_startup_complete_with_id (const gchar *startup_id);

Indicates to the GUI environment that the application has finished loading, using a given identifier.

GTK+ will call this function automatically for GtkWindow with custom startup-notification identifier unless gtk_window_set_auto_startup_notification() is called to disable that feature.

Parameters

startup_id

a startup-notification identifier, for which notification process should be completed

 

Since: 2.12


gdk_set_allowed_backends ()

void
gdk_set_allowed_backends (const gchar *backends);

Sets a list of backends that GDK should try to use.

This can be be useful if your application does not work with certain GDK backends.

By default, GDK tries all included backends.

For example,

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gdk_set_allowed_backends ("wayland,quartz,*");

instructs GDK to try the Wayland backend first, followed by the Quartz backend, and then all others.

If the GDK_BACKEND environment variable is set, it determines what backends are tried in what order, while still respecting the set of allowed backends that are specified by this function.

The possible backend names are x11, win32, quartz, broadway, wayland. You can also include a * in the list to try all remaining backends.

This call must happen prior to gdk_display_open(), gtk_init(), gtk_init_with_args() or gtk_init_check() in order to take effect.

Parameters

backends

a comma-separated list of backends

 

Since: 3.10


gdk_get_program_class ()

const gchar *
gdk_get_program_class (void);

Gets the program class. Unless the program class has explicitly been set with gdk_set_program_class() or with the --class commandline option, the default value is the program name (determined with g_get_prgname()) with the first character converted to uppercase.

Returns

the program class.


gdk_set_program_class ()

void
gdk_set_program_class (const gchar *program_class);

Sets the program class. The X11 backend uses the program class to set the class name part of the WM_CLASS property on toplevel windows; see the ICCCM.

The program class can still be overridden with the --class command line option.

Parameters

program_class

a string.

 

gdk_get_display ()

gchar *
gdk_get_display (void);

gdk_get_display has been deprecated since version 3.8 and should not be used in newly-written code.

Call gdk_display_get_name (gdk_display_get_default())) instead.

Gets the name of the display, which usually comes from the DISPLAY environment variable or the --display command line option.

Returns

the name of the display.


gdk_flush ()

void
gdk_flush (void);

Flushes the output buffers of all display connections and waits until all requests have been processed. This is rarely needed by applications.


gdk_screen_width ()

gint
gdk_screen_width (void);

Gets the width of the default screen in pixels. The returned size is in ”application pixels”, not in ”device pixels” (see gdk_screen_get_monitor_scale_factor()).

Returns

the width of the default screen in pixels.


gdk_screen_height ()

gint
gdk_screen_height (void);

Gets the height of the default screen in pixels. The returned size is in ”application pixels”, not in ”device pixels” (see gdk_screen_get_monitor_scale_factor()).

Returns

the height of the default screen in pixels.


gdk_screen_width_mm ()

gint
gdk_screen_width_mm (void);

Returns the width of the default screen in millimeters. Note that on many X servers this value will not be correct.

Returns

the width of the default screen in millimeters, though it is not always correct.


gdk_screen_height_mm ()

gint
gdk_screen_height_mm (void);

Returns the height of the default screen in millimeters. Note that on many X servers this value will not be correct.

Returns

the height of the default screen in millimeters, though it is not always correct.


gdk_pointer_grab ()

GdkGrabStatus
gdk_pointer_grab (GdkWindow *window,
                  gboolean owner_events,
                  GdkEventMask event_mask,
                  GdkWindow *confine_to,
                  GdkCursor *cursor,
                  guint32 time_);

gdk_pointer_grab has been deprecated since version 3.0 and should not be used in newly-written code.

Use gdk_device_grab() instead.

Grabs the pointer (usually a mouse) so that all events are passed to this application until the pointer is ungrabbed with gdk_pointer_ungrab(), or the grab window becomes unviewable. This overrides any previous pointer grab by this client.

Pointer grabs are used for operations which need complete control over mouse events, even if the mouse leaves the application. For example in GTK+ it is used for Drag and Drop, for dragging the handle in the GtkHPaned and GtkVPaned widgets.

Note that if the event mask of an X window has selected both button press and button release events, then a button press event will cause an automatic pointer grab until the button is released. X does this automatically since most applications expect to receive button press and release events in pairs. It is equivalent to a pointer grab on the window with owner_events set to TRUE.

If you set up anything at the time you take the grab that needs to be cleaned up when the grab ends, you should handle the GdkEventGrabBroken events that are emitted when the grab ends unvoluntarily.

Parameters

window

the GdkWindow which will own the grab (the grab window).

 

owner_events

if FALSE then all pointer events are reported with respect to window and are only reported if selected by event_mask . If TRUE then pointer events for this application are reported as normal, but pointer events outside this application are reported with respect to window and only if selected by event_mask . In either mode, unreported events are discarded.

 

event_mask

specifies the event mask, which is used in accordance with owner_events . Note that only pointer events (i.e. button and motion events) may be selected.

 

confine_to

If non-NULL, the pointer will be confined to this window during the grab. If the pointer is outside confine_to , it will automatically be moved to the closest edge of confine_to and enter and leave events will be generated as necessary.

[allow-none]

cursor

the cursor to display while the grab is active. If this is NULL then the normal cursors are used for window and its descendants, and the cursor for window is used for all other windows.

[allow-none]

time_

the timestamp of the event which led to this pointer grab. This usually comes from a GdkEventButton struct, though GDK_CURRENT_TIME can be used if the time isn’t known.

 

Returns

GDK_GRAB_SUCCESS if the grab was successful.


gdk_pointer_ungrab ()

void
gdk_pointer_ungrab (guint32 time_);

gdk_pointer_ungrab has been deprecated since version 3.0 and should not be used in newly-written code.

Use gdk_device_ungrab(), together with gdk_device_grab() instead.

Ungrabs the pointer on the default display, if it is grabbed by this application.

Parameters

time_

a timestamp from a GdkEvent, or GDK_CURRENT_TIME if no timestamp is available.

 

gdk_pointer_is_grabbed ()

gboolean
gdk_pointer_is_grabbed (void);

gdk_pointer_is_grabbed has been deprecated since version 3.0 and should not be used in newly-written code.

Use gdk_display_device_is_grabbed() instead.

Returns TRUE if the pointer on the default display is currently grabbed by this application.

Note that this does not take the inmplicit pointer grab on button presses into account.

Returns

TRUE if the pointer is currently grabbed by this application.


gdk_set_double_click_time ()

void
gdk_set_double_click_time (guint msec);

Set the double click time for the default display. See gdk_display_set_double_click_time(). See also gdk_display_set_double_click_distance(). Applications should not set this, it is a global user-configured setting.

Parameters

msec

double click time in milliseconds (thousandths of a second)

 

gdk_keyboard_grab ()

GdkGrabStatus
gdk_keyboard_grab (GdkWindow *window,
                   gboolean owner_events,
                   guint32 time_);

gdk_keyboard_grab has been deprecated since version 3.0 and should not be used in newly-written code.

Use gdk_device_grab() instead.

Grabs the keyboard so that all events are passed to this application until the keyboard is ungrabbed with gdk_keyboard_ungrab(). This overrides any previous keyboard grab by this client.

If you set up anything at the time you take the grab that needs to be cleaned up when the grab ends, you should handle the GdkEventGrabBroken events that are emitted when the grab ends unvoluntarily.

Parameters

window

the GdkWindow which will own the grab (the grab window).

 

owner_events

if FALSE then all keyboard events are reported with respect to window . If TRUE then keyboard events for this application are reported as normal, but keyboard events outside this application are reported with respect to window . Both key press and key release events are always reported, independant of the event mask set by the application.

 

time_

a timestamp from a GdkEvent, or GDK_CURRENT_TIME if no timestamp is available.

 

Returns

GDK_GRAB_SUCCESS if the grab was successful.


gdk_keyboard_ungrab ()

void
gdk_keyboard_ungrab (guint32 time_);

gdk_keyboard_ungrab has been deprecated since version 3.0 and should not be used in newly-written code.

Use gdk_device_ungrab(), together with gdk_device_grab() instead.

Ungrabs the keyboard on the default display, if it is grabbed by this application.

Parameters

time_

a timestamp from a GdkEvent, or GDK_CURRENT_TIME if no timestamp is available.

 

gdk_beep ()

void
gdk_beep (void);

Emits a short beep on the default display.


gdk_error_trap_push ()

void
gdk_error_trap_push (void);

This function allows X errors to be trapped instead of the normal behavior of exiting the application. It should only be used if it is not possible to avoid the X error in any other way. Errors are ignored on all GdkDisplay currently known to the GdkDisplayManager. If you don’t care which error happens and just want to ignore everything, pop with gdk_error_trap_pop_ignored(). If you need the error code, use gdk_error_trap_pop() which may have to block and wait for the error to arrive from the X server.

This API exists on all platforms but only does anything on X.

You can use gdk_x11_display_error_trap_push() to ignore errors on only a single display.

Trapping an X error

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gdk_error_trap_push ();

 // ... Call the X function which may cause an error here ...


if (gdk_error_trap_pop ())
 {
   // ... Handle the error here ...
 }


gdk_error_trap_pop ()

gint
gdk_error_trap_pop (void);

Removes an error trap pushed with gdk_error_trap_push(). May block until an error has been definitively received or not received from the X server. gdk_error_trap_pop_ignored() is preferred if you don’t need to know whether an error occurred, because it never has to block. If you don't need the return value of gdk_error_trap_pop(), use gdk_error_trap_pop_ignored().

Prior to GDK 3.0, this function would not automatically sync for you, so you had to gdk_flush() if your last call to Xlib was not a blocking round trip.

Returns

X error code or 0 on success


gdk_error_trap_pop_ignored ()

void
gdk_error_trap_pop_ignored (void);

Removes an error trap pushed with gdk_error_trap_push(), but without bothering to wait and see whether an error occurred. If an error arrives later asynchronously that was triggered while the trap was pushed, that error will be ignored.

Since: 3.0

Types and Values

enum GdkGrabStatus

Returned by gdk_device_grab(), gdk_pointer_grab() and gdk_keyboard_grab() to indicate success or the reason for the failure of the grab attempt.

Members

GDK_GRAB_SUCCESS

the resource was successfully grabbed.

 

GDK_GRAB_ALREADY_GRABBED

the resource is actively grabbed by another client.

 

GDK_GRAB_INVALID_TIME

the resource was grabbed more recently than the specified time.

 

GDK_GRAB_NOT_VIEWABLE

the grab window or the confine_to window are not viewable.

 

GDK_GRAB_FROZEN

the resource is frozen by an active grab of another client.

 

GDK_GRAB_FAILED

the grab failed for some other reason. Since 3.16

 

GDK_WINDOWING_X11

#define GDK_WINDOWING_X11

The GDK_WINDOWING_X11 macro is defined if the X11 backend is supported.

Use this macro to guard code that is specific to the X11 backend.


GDK_WINDOWING_WIN32

#define GDK_WINDOWING_WIN32

The GDK_WINDOWING_WIN32 macro is defined if the Win32 backend is supported.

Use this macro to guard code that is specific to the Win32 backend.


GDK_WINDOWING_QUARTZ

#define GDK_WINDOWING_QUARTZ

The GDK_WINDOWING_QUARTZ macro is defined if the Quartz backend is supported.

Use this macro to guard code that is specific to the Quartz backend.


GDK_WINDOWING_WAYLAND

#define GDK_WINDOWING_WAYLAND

The GDK_WINDOWING_WAYLAND macro is defined if the Wayland backend is supported.

Use this macro to guard code that is specific to the Wayland backend.


GDK_VERSION_3_0

#define GDK_VERSION_3_0         (G_ENCODE_VERSION (3, 0))

A macro that evaluates to the 3.0 version of GDK, in a format that can be used by the C pre-processor.

Since: 3.4


GDK_VERSION_3_2

#define GDK_VERSION_3_2         (G_ENCODE_VERSION (3, 2))

A macro that evaluates to the 3.2 version of GDK, in a format that can be used by the C pre-processor.

Since: 3.4


GDK_VERSION_3_4

#define GDK_VERSION_3_4         (G_ENCODE_VERSION (3, 4))

A macro that evaluates to the 3.4 version of GDK, in a format that can be used by the C pre-processor.

Since: 3.4


GDK_VERSION_3_6

#define GDK_VERSION_3_6         (G_ENCODE_VERSION (3, 6))

A macro that evaluates to the 3.6 version of GDK, in a format that can be used by the C pre-processor.

Since: 3.6


GDK_VERSION_3_8

#define GDK_VERSION_3_8         (G_ENCODE_VERSION (3, 8))

A macro that evaluates to the 3.8 version of GDK, in a format that can be used by the C pre-processor.

Since: 3.8


GDK_VERSION_3_10

#define GDK_VERSION_3_10        (G_ENCODE_VERSION (3, 10))

A macro that evaluates to the 3.10 version of GDK, in a format that can be used by the C pre-processor.

Since: 3.10


GDK_VERSION_3_12

#define GDK_VERSION_3_12        (G_ENCODE_VERSION (3, 12))

A macro that evaluates to the 3.12 version of GDK, in a format that can be used by the C pre-processor.

Since: 3.12


GDK_VERSION_3_14

#define GDK_VERSION_3_14        (G_ENCODE_VERSION (3, 14))

A macro that evaluates to the 3.14 version of GDK, in a format that can be used by the C pre-processor.

Since: 3.14


GDK_VERSION_MIN_REQUIRED

# define GDK_VERSION_MIN_REQUIRED      (GDK_VERSION_CUR_STABLE)

A macro that should be defined by the user prior to including the gdk.h header. The definition should be one of the predefined GDK version macros: GDK_VERSION_3_0, GDK_VERSION_3_2,...

This macro defines the lower bound for the GDK API to use.

If a function has been deprecated in a newer version of GDK, it is possible to use this symbol to avoid the compiler warnings without disabling warning for every deprecated function.

Since: 3.4


GDK_VERSION_MAX_ALLOWED

#  define GDK_VERSION_MAX_ALLOWED      GDK_VERSION_MIN_REQUIRED

A macro that should be defined by the user prior to including the gdk.h header. The definition should be one of the predefined GDK version macros: GDK_VERSION_3_0, GDK_VERSION_3_2,...

This macro defines the upper bound for the GDK API to use.

If a function has been introduced in a newer version of GDK, it is possible to use this symbol to get compiler warnings when trying to use that function.

Since: 3.4


GDK_DISABLE_DEPRECATION_WARNINGS

#define GDK_DISABLE_DEPRECATION_WARNINGS

A macro that should be defined before including the gdk.h header. If it is defined, no compiler warnings will be produced for uses of deprecated GDK APIs.

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