<!-- ##### SECTION Title ##### -->General<!-- ##### SECTION Short_Description ##### -->Library initialization and miscellaneous functions<!-- ##### SECTION Long_Description ##### --><para>This section describes the GDK initialization functions and miscellaneousutility functions.</para><!-- ##### SECTION See_Also ##### --><para></para><!-- ##### SECTION Stability_Level ##### --><!-- ##### FUNCTION gdk_init ##### --><para>Initializes the GDK library and connects to the X server.If initialization fails, a warning message is output and the applicationterminates with a call to <literal>exit(1)</literal>.</para><para>Any arguments used by GDK are removed from the array and @argc and @argv areupdated accordingly.</para><para>GTK+ initializes GDK in gtk_init() and so this function is not usually neededby GTK+ applications.</para>@argc: the number of command line arguments.@argv: the array of command line arguments.<!-- ##### FUNCTION gdk_init_check ##### --><para>Initializes the GDK library and connects to the X server, returning %TRUE onsuccess.</para><para>Any arguments used by GDK are removed from the array and @argc and @argv areupdated accordingly.</para><para>GTK+ initializes GDK in gtk_init() and so this function is not usually neededby GTK+ applications.</para>@argc: the number of command line arguments.@argv: the array of command line arguments.@Returns: %TRUE if initialization succeeded.<!-- ##### FUNCTION gdk_parse_args ##### --><para></para>@argc: @argv: <!-- ##### FUNCTION gdk_get_display_arg_name ##### --><para></para>@Returns: <!-- ##### FUNCTION gdk_set_locale ##### --><para>Initializes the support for internationalization by calling the <function>setlocale()</function>system call. This function is called by gtk_set_locale() and so GTK+applications should use that instead.</para><para>The locale to use is determined by the <envar>LANG</envar> environment variable,so to run an application in a certain locale you can do something like this:<informalexample><programlisting>  export LANG="fr"  ... run application ...</programlisting></informalexample></para><para>If the locale is not supported by X then it is reset to the standard "C"locale.</para>@Returns: the resulting locale.<!-- ##### FUNCTION gdk_set_sm_client_id ##### --><para></para>@sm_client_id: <!-- ##### FUNCTION gdk_exit ##### --><para>Exits the application using the <function>exit()</function> system call.</para><para>This routine is provided mainly for backwards compatibility, since it used toperform tasks necessary to exit the application cleanly. Those tasks are nowperformed in a function which is automatically called on exit (via the useof g_atexit()).</para>@error_code: the error code to pass to the <function>exit()</function> call.<!-- ##### FUNCTION gdk_notify_startup_complete ##### --><para></para><!-- ##### FUNCTION gdk_notify_startup_complete_with_id ##### --><para></para>@startup_id: <!-- ##### FUNCTION gdk_get_program_class ##### --><para>Gets the program class. Unless the program class has explicitlybeen set with gdk_set_program_class() or with the <option>--class</option> commandline option, the default value is the program name (determined with g_get_prgname()) with the first character converted to uppercase. </para>@Returns: the program class.<!-- ##### FUNCTION gdk_set_program_class ##### --><para>Sets the program class. The X11 backend uses the program class to setthe class name part of the <literal>WM_CLASS</literal> property ontoplevel windows; see the ICCCM.</para>@program_class: a string.<!-- ##### FUNCTION gdk_get_display ##### --><para>Gets the name of the display, which usually comes from the <envar>DISPLAY</envar>environment variable or the <option>--display</option> command line option.</para>@Returns: the name of the display.<!-- ##### FUNCTION gdk_flush ##### --><para>Flushes the X output buffer and waits until all requests have been processedby the server. This is rarely needed by applications. It's main use is fortrapping X errors with gdk_error_trap_push() and gdk_error_trap_pop().</para><!-- ##### FUNCTION gdk_screen_width ##### --><para></para>@Returns: <!-- ##### FUNCTION gdk_screen_height ##### --><para></para>@Returns: <!-- ##### FUNCTION gdk_screen_width_mm ##### --><para></para>@Returns: <!-- ##### FUNCTION gdk_screen_height_mm ##### --><para></para>@Returns: <!-- ##### FUNCTION gdk_pointer_grab ##### --><para>Grabs the pointer (usually a mouse) so that all events are passed to thisapplication until the pointer is ungrabbed with gdk_pointer_ungrab(), orthe grab window becomes unviewable.This overrides any previous pointer grab by this client.</para><para>Pointer grabs are used for operations which need complete control over mouseevents, even if the mouse leaves the application.For example in GTK+ it is used for Drag and Drop, for dragging the handle inthe #GtkHPaned and #GtkVPaned widgets, and for resizing columns in #GtkCListwidgets.</para><para>Note that if the event mask of an X window has selected both button press andbutton release events, then a button press event will cause an automaticpointer grab until the button is released.X does this automatically since most applications expect to receive buttonpress and release events in pairs.It is equivalent to a pointer grab on the window with @owner_events set to%TRUE.</para><para>If you set up anything at the time you take the grab that needs to be cleanedup when the grab ends, you should handle the #GdkEventGrabBroken events thatare emitted when the grab ends unvoluntarily.</para>@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 pointerevents for this application are reported as normal, but pointer events outsidethis 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 thiswindow during the grab. If the pointer is outside @confine_to, it willautomatically be moved to the closest edge of @confine_to and enterand leave events will be generated as necessary.@cursor: the cursor to display while the grab is active. If this is %NULL thenthe normal cursors are used for @window and its descendants, and the cursorfor @window is used for all other windows.@time_: the timestamp of the event which led to this pointer grab. This usuallycomes from a #GdkEventButton struct, though %GDK_CURRENT_TIME can be used ifthe time isn't known.@Returns: %GDK_GRAB_SUCCESS if the grab was successful.<!-- ##### ENUM GdkGrabStatus ##### --><para>Returned by gdk_pointer_grab() and gdk_keyboard_grab() to indicate success or the reason for the failure of the grab attempt.</para>@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.<!-- ##### FUNCTION gdk_pointer_ungrab ##### --><para></para>@time_: <!-- ##### FUNCTION gdk_pointer_is_grabbed ##### --><para></para><para></para>@Returns: <!-- ##### FUNCTION gdk_set_double_click_time ##### --><para></para>@msec: <!-- ##### FUNCTION gdk_keyboard_grab ##### --><para>Grabs the keyboard so that all events are passed to thisapplication until the keyboard is ungrabbed with gdk_keyboard_ungrab().This overrides any previous keyboard grab by this client.</para><para>If you set up anything at the time you take the grab that needs to be cleanedup when the grab ends, you should handle the #GdkEventGrabBroken events thatare emitted when the grab ends unvoluntarily.</para>@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 asnormal, but keyboard events outside this application are reported with respectto @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 isavailable.@Returns: %GDK_GRAB_SUCCESS if the grab was successful.<!-- ##### FUNCTION gdk_keyboard_ungrab ##### --><para></para>@time_: <!-- ##### FUNCTION gdk_beep ##### --><para></para><!-- ##### FUNCTION gdk_get_use_xshm ##### --><para>Returns %TRUE if GDK will attempt to use the MIT-SHM shared memory extension.</para><para>The shared memory extension is used for #GdkImage, and consequently for<link linkend="gdk-GdkRGB">GdkRGB</link>.It enables much faster drawing by communicating with the X server throughSYSV shared memory calls. However, it can only be used if the X client andserver are on the same machine and the server supports it.</para>@Returns: %TRUE if use of the MIT shared memory extension will be attempted.<!-- ##### FUNCTION gdk_set_use_xshm ##### --><para>Sets whether the use of the MIT shared memory extension should be attempted.This function is mainly for internal use. It is only safe for an applicationto set this to %FALSE, since if it is set to %TRUE and the server does notsupport the extension it may cause warning messages to be output.</para>@use_xshm: %TRUE if use of the MIT shared memory extension should be attempted.<!-- ##### FUNCTION gdk_error_trap_push ##### --><para>This function allows X errors to be trapped instead of the normal behaviorof exiting the application. It should only be used if it is not possible toavoid the X error in any other way.</para><example><title>Trapping an X error</title><programlisting>  gdk_error_trap_push (<!-- -->);  /* ... Call the X function which may cause an error here ... */  /* Flush the X queue to catch errors now. */  gdk_flush (<!-- -->);  if (gdk_error_trap_pop (<!-- -->))    {      /* ... Handle the error here ... */    }</programlisting></example><!-- ##### FUNCTION gdk_error_trap_pop ##### --><para>Removes the X error trap installed with gdk_error_trap_push().</para>@Returns: the X error code, or 0 if no error occurred.<!-- ##### MACRO GDK_WINDOWING_X11 ##### --><para>This macro is defined if GDK is configured to use the X backend.</para><!-- ##### MACRO GDK_WINDOWING_WIN32 ##### --><para>This macro is defined if GDK is configured to use the Win32 backend.</para>