g_application_id_is_valid ()

gboolean
g_application_id_is_valid (const gchar *application_id);

Checks if application_id is a valid application identifier.

A valid ID is required for calls to g_application_new() and g_application_set_application_id().

For convenience, the restrictions on application identifiers are reproduced here:

g_application_new ()

GApplication *
g_application_new (const gchar *application_id,
                   GApplicationFlags flags);

Creates a new GApplication instance.

If non-NULL, the application id must be valid. See g_application_id_is_valid().

If no application ID is given then some features of GApplication (most notably application uniqueness) will be disabled.

g_application_get_application_id ()

const gchar *
g_application_get_application_id (GApplication *application);

Gets the unique identifier for application .

Since 2.28

g_application_set_application_id ()

void
g_application_set_application_id (GApplication *application,
                                  const gchar *application_id);

Sets the unique identifier for application .

The application id can only be modified if application has not yet been registered.

If non-NULL, the application id must be valid. See g_application_id_is_valid().

Since 2.28

g_application_get_inactivity_timeout ()

guint
g_application_get_inactivity_timeout (GApplication *application);

Gets the current inactivity timeout for the application.

This is the amount of time (in milliseconds) after the last call to g_application_release() before the application stops running.

Since 2.28

g_application_set_inactivity_timeout ()

void
g_application_set_inactivity_timeout (GApplication *application,
                                      guint inactivity_timeout);

Sets the current inactivity timeout for the application.

This is the amount of time (in milliseconds) after the last call to g_application_release() before the application stops running.

This call has no side effects of its own. The value set here is only used for next time g_application_release() drops the use count to zero. Any timeouts currently in progress are not impacted.

Since 2.28

g_application_get_flags ()

GApplicationFlags
g_application_get_flags (GApplication *application);

Gets the flags for application .

See GApplicationFlags.

Since 2.28

g_application_set_flags ()

void
g_application_set_flags (GApplication *application,
                         GApplicationFlags flags);

Sets the flags for application .

The flags can only be modified if application has not yet been registered.

See GApplicationFlags.

Since 2.28

g_application_get_resource_base_path ()

const gchar *
g_application_get_resource_base_path (GApplication *application);

Gets the resource base path of application .

See g_application_set_resource_base_path() for more information.

Since 2.42

g_application_set_resource_base_path ()

void
g_application_set_resource_base_path (GApplication *application,
                                      const gchar *resource_path);

Sets (or unsets) the base resource path of application .

The path is used to automatically load various application resources such as menu layouts and action descriptions. The various types of resources will be found at fixed names relative to the given base path.

By default, the resource base path is determined from the application ID by prefixing '/' and replacing each '.' with '/'. This is done at the time that the GApplication object is constructed. Changes to the application ID after that point will not have an impact on the resource base path.

As an example, if the application has an ID of "org.example.app" then the default resource base path will be "/org/example/app". If this is a GtkApplication (and you have not manually changed the path) then Gtk will then search for the menus of the application at "/org/example/app/gtk/menus.ui".

See GResource for more information about adding resources to your application.

You can disable automatic resource loading functionality by setting the path to NULL.

Changing the resource base path once the application is running is not recommended. The point at which the resource path is consulted for forming paths for various purposes is unspecified.

Since 2.42

g_application_get_dbus_connection ()

GDBusConnection *
g_application_get_dbus_connection (GApplication *application);

Gets the GDBusConnection being used by the application, or NULL.

If GApplication is using its D-Bus backend then this function will return the GDBusConnection being used for uniqueness and communication with the desktop environment and other instances of the application.

If GApplication is not using D-Bus then this function will return NULL. This includes the situation where the D-Bus backend would normally be in use but we were unable to connect to the bus.

This function must not be called before the application has been registered. See g_application_get_is_registered().

Since 2.34

g_application_get_dbus_object_path ()

const gchar *
g_application_get_dbus_object_path (GApplication *application);

Gets the D-Bus object path being used by the application, or NULL.

If GApplication is using its D-Bus backend then this function will return the D-Bus object path that GApplication is using. If the application is the primary instance then there is an object published at this path. If the application is not the primary instance then the result of this function is undefined.

If GApplication is not using D-Bus then this function will return NULL. This includes the situation where the D-Bus backend would normally be in use but we were unable to connect to the bus.

This function must not be called before the application has been registered. See g_application_get_is_registered().

Since 2.34

g_application_set_action_group ()

void
g_application_set_action_group (GApplication *application,
                                GActionGroup *action_group);

This used to be how actions were associated with a GApplication. Now there is GActionMap for that.

Since 2.28

g_application_get_is_registered ()

gboolean
g_application_get_is_registered (GApplication *application);

Checks if application is registered.

An application is registered if g_application_register() has been successfully called.

Since 2.28

g_application_get_is_remote ()

gboolean
g_application_get_is_remote (GApplication *application);

Checks if application is remote.

If application is remote then it means that another instance of application already exists (the 'primary' instance). Calls to perform actions on application will result in the actions being performed by the primary instance.

The value of this property cannot be accessed before g_application_register() has been called. See g_application_get_is_registered().

Since 2.28

g_application_register ()

gboolean
g_application_register (GApplication *application,
                        GCancellable *cancellable,
                        GError **error);

Attempts registration of the application.

This is the point at which the application discovers if it is the primary instance or merely acting as a remote for an already-existing primary instance. This is implemented by attempting to acquire the application identifier as a unique bus name on the session bus using GDBus.

If there is no application ID or if G_APPLICATION_NON_UNIQUE was given, then this process will always become the primary instance.

Due to the internal architecture of GDBus, method calls can be dispatched at any time (even if a main loop is not running). For this reason, you must ensure that any object paths that you wish to register are registered before calling this function.

If the application has already been registered then TRUE is returned with no work performed.

The “startup” signal is emitted if registration succeeds and application is the primary instance (including the non-unique case).

In the event of an error (such as cancellable being cancelled, or a failure to connect to the session bus), FALSE is returned and error is set appropriately.

Note: the return value of this function is not an indicator that this instance is or is not the primary instance of the application. See g_application_get_is_remote() for that.

Since 2.28

g_application_hold ()

void
g_application_hold (GApplication *application);

Increases the use count of application .

Use this function to indicate that the application has a reason to continue to run. For example, g_application_hold() is called by GTK+ when a toplevel window is on the screen.

To cancel the hold, call g_application_release().

g_application_release ()

void
g_application_release (GApplication *application);

Decrease the use count of application .

When the use count reaches zero, the application will stop running.

Never call this function except to cancel the effect of a previous call to g_application_hold().

g_application_quit ()

void
g_application_quit (GApplication *application);

Immediately quits the application.

Upon return to the mainloop, g_application_run() will return, calling only the 'shutdown' function before doing so.

The hold count is ignored.

The result of calling g_application_run() again after it returns is unspecified.

Since 2.32

g_application_activate ()

void
g_application_activate (GApplication *application);

Activates the application.

In essence, this results in the “activate” signal being emitted in the primary instance.

The application must be registered before calling this function.

Since 2.28

g_application_open ()

void
g_application_open (GApplication *application,
                    GFile **files,
                    gint n_files,
                    const gchar *hint);

Opens the given files.

In essence, this results in the “open” signal being emitted in the primary instance.

n_files must be greater than zero.

hint is simply passed through to the ::open signal. It is intended to be used by applications that have multiple modes for opening files (eg: "view" vs "edit", etc). Unless you have a need for this functionality, you should use "".

The application must be registered before calling this function and it must have the G_APPLICATION_HANDLES_OPEN flag set.

Since 2.28

g_application_send_notification ()

void
g_application_send_notification (GApplication *application,
                                 const gchar *id,
                                 GNotification *notification);

Sends a notification on behalf of application to the desktop shell. There is no guarantee that the notification is displayed immediately, or even at all.

Notifications may persist after the application exits. It will be D-Bus-activated when the notification or one of its actions is activated.

Modifying notification after this call has no effect. However, the object can be reused for a later call to this function.

id may be any string that uniquely identifies the event for the application. It does not need to be in any special format. For example, "new-message" might be appropriate for a notification about new messages.

If a previous notification was sent with the same id , it will be replaced with notification and shown again as if it was a new notification. This works even for notifications sent from a previous execution of the application, as long as id is the same string.

id may be NULL, but it is impossible to replace or withdraw notifications without an id.

If notification is no longer relevant, it can be withdrawn with g_application_withdraw_notification().

Since 2.40

g_application_withdraw_notification ()

void
g_application_withdraw_notification (GApplication *application,
                                     const gchar *id);

Withdraws a notification that was sent with g_application_send_notification().

This call does nothing if a notification with id doesn't exist or the notification was never sent.

This function works even for notifications sent in previous executions of this application, as long id is the same as it was for the sent notification.

Note that notifications are dismissed when the user clicks on one of the buttons in a notification or triggers its default action, so there is no need to explicitly withdraw the notification in that case.

Since 2.40

g_application_run ()

int
g_application_run (GApplication *application,
                   int argc,
                   char **argv);

Runs the application.

This function is intended to be run from main() and its return value is intended to be returned by main(). Although you are expected to pass the argc , argv parameters from main() to this function, it is possible to pass NULL if argv is not available or commandline handling is not required. Note that on Windows, argc and argv are ignored, and g_win32_get_command_line() is called internally (for proper support of Unicode commandline arguments).

GApplication will attempt to parse the commandline arguments. You can add commandline flags to the list of recognised options by way of g_application_add_main_option_entries(). After this, the “handle-local-options” signal is emitted, from which the application can inspect the values of its GOptionEntrys.

“handle-local-options” is a good place to handle options such as --version, where an immediate reply from the local process is desired (instead of communicating with an already-running instance). A “handle-local-options” handler can stop further processing by returning a non-negative value, which then becomes the exit status of the process.

What happens next depends on the flags: if G_APPLICATION_HANDLES_COMMAND_LINE was specified then the remaining commandline arguments are sent to the primary instance, where a “command-line” signal is emitted. Otherwise, the remaining commandline arguments are assumed to be a list of files. If there are no files listed, the application is activated via the “activate” signal. If there are one or more files, and G_APPLICATION_HANDLES_OPEN was specified then the files are opened via the “open” signal.

If you are interested in doing more complicated local handling of the commandline then you should implement your own GApplication subclass and override local_command_line(). In this case, you most likely want to return TRUE from your local_command_line() implementation to suppress the default handling. See gapplication-example-cmdline2.c for an example.

If, after the above is done, the use count of the application is zero then the exit status is returned immediately. If the use count is non-zero then the default main context is iterated until the use count falls to zero, at which point 0 is returned.

If the G_APPLICATION_IS_SERVICE flag is set, then the service will run for as much as 10 seconds with a use count of zero while waiting for the message that caused the activation to arrive. After that, if the use count falls to zero the application will exit immediately, except in the case that g_application_set_inactivity_timeout() is in use.

This function sets the prgname (g_set_prgname()), if not already set, to the basename of argv[0].

Since 2.40, applications that are not explicitly flagged as services or launchers (ie: neither G_APPLICATION_IS_SERVICE or G_APPLICATION_IS_LAUNCHER are given as flags) will check (from the default handler for local_command_line) if "--gapplication-service" was given in the command line. If this flag is present then normal commandline processing is interrupted and the G_APPLICATION_IS_SERVICE flag is set. This provides a "compromise" solution whereby running an application directly from the commandline will invoke it in the normal way (which can be useful for debugging) while still allowing applications to be D-Bus activated in service mode. The D-Bus service file should invoke the executable with "--gapplication-service" as the sole commandline argument. This approach is suitable for use by most graphical applications but should not be used from applications like editors that need precise control over when processes invoked via the commandline will exit and what their exit status will be.

Since 2.28

g_application_add_main_option_entries ()

void
g_application_add_main_option_entries (GApplication *application,
                                       const GOptionEntry *entries);

Adds main option entries to be handled by application .

This function is comparable to g_option_context_add_main_entries().

After the commandline arguments are parsed, the “handle-local-options” signal will be emitted. At this point, the application can inspect the values pointed to by arg_data in the given GOptionEntrys.

Unlike GOptionContext, GApplication supports giving a NULL arg_data for a non-callback GOptionEntry. This results in the argument in question being packed into a GVariantDict which is also passed to “handle-local-options”, where it can be inspected and modified. If G_APPLICATION_HANDLES_COMMAND_LINE is set, then the resulting dictionary is sent to the primary instance, where g_application_command_line_get_options_dict() will return it. This "packing" is done according to the type of the argument -- booleans for normal flags, strings for strings, bytestrings for filenames, etc. The packing only occurs if the flag is given (ie: we do not pack a "false" GVariant in the case that a flag is missing).

In general, it is recommended that all commandline arguments are parsed locally. The options dictionary should then be used to transmit the result of the parsing to the primary instance, where g_variant_dict_lookup() can be used. For local options, it is possible to either use arg_data in the usual way, or to consult (and potentially remove) the option from the options dictionary.

This function is new in GLib 2.40. Before then, the only real choice was to send all of the commandline arguments (options and all) to the primary instance for handling. GApplication ignored them completely on the local side. Calling this function "opts in" to the new behaviour, and in particular, means that unrecognised options will be treated as errors. Unrecognised options have never been ignored when G_APPLICATION_HANDLES_COMMAND_LINE is unset.

If “handle-local-options” needs to see the list of filenames, then the use of G_OPTION_REMAINING is recommended. If arg_data is NULL then G_OPTION_REMAINING can be used as a key into the options dictionary. If you do use G_OPTION_REMAINING then you need to handle these arguments for yourself because once they are consumed, they will no longer be visible to the default handling (which treats them as filenames to be opened).

Since 2.40

g_application_add_main_option ()

void
g_application_add_main_option (GApplication *application,
                               const char *long_name,
                               char short_name,
                               GOptionFlags flags,
                               GOptionArg arg,
                               const char *description,
                               const char *arg_description);

Add an option to be handled by application .

Calling this function is the equivalent of calling g_application_add_main_option_entries() with a single GOptionEntry that has its arg_data member set to NULL.

The parsed arguments will be packed into a GVariantDict which is passed to “handle-local-options”. If G_APPLICATION_HANDLES_COMMAND_LINE is set, then it will also be sent to the primary instance. See g_application_add_main_option_entries() for more details.

See GOptionEntry for more documentation of the arguments.

Since 2.42

g_application_add_option_group ()

void
g_application_add_option_group (GApplication *application,
                                GOptionGroup *group);

Adds a GOptionGroup to the commandline handling of application .

This function is comparable to g_option_context_add_group().

Unlike g_application_add_main_option_entries(), this function does not deal with NULL arg_data and never transmits options to the primary instance.

The reason for that is because, by the time the options arrive at the primary instance, it is typically too late to do anything with them. Taking the GTK option group as an example: GTK will already have been initialised by the time the “command-line” handler runs. In the case that this is not the first-running instance of the application, the existing instance may already have been running for a very long time.

This means that the options from GOptionGroup are only really usable in the case that the instance of the application being run is the first instance. Passing options like --display= or --gdk-debug= on future runs will have no effect on the existing primary instance.

Calling this function will cause the options in the supplied option group to be parsed, but it does not cause you to be "opted in" to the new functionality whereby unrecognised options are rejected even if G_APPLICATION_HANDLES_COMMAND_LINE was given.

Since 2.40

g_application_set_default ()

void
g_application_set_default (GApplication *application);

Sets or unsets the default application for the process, as returned by g_application_get_default().

This function does not take its own reference on application . If application is destroyed then the default application will revert back to NULL.

Since 2.32

g_application_get_default ()

GApplication *
g_application_get_default (void);

Returns the default GApplication instance for this process.

Normally there is only one GApplication per process and it becomes the default when it is created. You can exercise more control over this by using g_application_set_default().

If there is no default application then NULL is returned.

Since 2.32

g_application_mark_busy ()

void
g_application_mark_busy (GApplication *application);

Increases the busy count of application .

Use this function to indicate that the application is busy, for instance while a long running operation is pending.

The busy state will be exposed to other processes, so a session shell will use that information to indicate the state to the user (e.g. with a spinner).

To cancel the busy indication, use g_application_unmark_busy().

Since 2.38

g_application_unmark_busy ()

void
g_application_unmark_busy (GApplication *application);

Decreases the busy count of application .

When the busy count reaches zero, the new state will be propagated to other processes.

This function must only be called to cancel the effect of a previous call to g_application_mark_busy().

Since 2.38

g_application_get_is_busy ()

gboolean
g_application_get_is_busy (GApplication *application);

Gets the application's current busy state, as set through g_application_mark_busy() or g_application_bind_busy_property().

Since 2.44

g_application_bind_busy_property ()

void
g_application_bind_busy_property (GApplication *application,
                                  gpointer object,
                                  const gchar *property);

Marks application as busy (see g_application_mark_busy()) while property on object is TRUE.

The binding holds a reference to application while it is active, but not to object . Instead, the binding is destroyed when object is finalized.

Since 2.44

g_application_unbind_busy_property ()

void
g_application_unbind_busy_property (GApplication *application,
                                    gpointer object,
                                    const gchar *property);

Destroys a binding between property and the busy state of application that was previously created with g_application_bind_busy_property().

Since 2.44

GApplication

typedef struct _GApplication GApplication;

GApplication is an opaque data structure and can only be accessed using the following functions.

Since 2.28

struct GApplicationClass

struct GApplicationClass {
  /* signals */
  void                      (* startup)             (GApplication              *application);

  void                      (* activate)            (GApplication              *application);

  void                      (* open)                (GApplication              *application,
                                                     GFile                    **files,
                                                     gint                       n_files,
                                                     const gchar               *hint);

  int                       (* command_line)        (GApplication              *application,
                                                     GApplicationCommandLine   *command_line);

  /* vfuncs */

  /**
   * GApplicationClass::local_command_line:
   * @application: a #GApplication
   * @arguments: (inout) (array zero-terminated=1): array of command line arguments
   * @exit_status: (out): exit status to fill after processing the command line.
   *
   * This virtual function is always invoked in the local instance. It
   * gets passed a pointer to a %NULL-terminated copy of @argv and is
   * expected to remove arguments that it handled (shifting up remaining
   * arguments).
   *
   * The last argument to local_command_line() is a pointer to the @status
   * variable which can used to set the exit status that is returned from
   * g_application_run().
   *
   * See g_application_run() for more details on #GApplication startup.
   *
   * Returns: %TRUE if the commandline has been completely handled
   */
  gboolean                  (* local_command_line)  (GApplication              *application,
                                                     gchar                   ***arguments,
                                                     int                       *exit_status);

  void                      (* before_emit)         (GApplication              *application,
                                                     GVariant                  *platform_data);
  void                      (* after_emit)          (GApplication              *application,
                                                     GVariant                  *platform_data);
  void                      (* add_platform_data)   (GApplication              *application,
                                                     GVariantBuilder           *builder);
  void                      (* quit_mainloop)       (GApplication              *application);
  void                      (* run_mainloop)        (GApplication              *application);
  void                      (* shutdown)            (GApplication              *application);

  gboolean                  (* dbus_register)       (GApplication              *application,
                                                     GDBusConnection           *connection,
                                                     const gchar               *object_path,
                                                     GError                   **error);
  void                      (* dbus_unregister)     (GApplication              *application,
                                                     GDBusConnection           *connection,
                                                     const gchar               *object_path);
  gint                      (* handle_local_options)(GApplication              *application,
                                                     GVariantDict              *options);
};

Virtual function table for GApplication.

Since 2.28

enum GApplicationFlags

Flags used to define the behaviour of a GApplication.

Since 2.28

The “action-group” property

  “action-group”             GActionGroup *

The group of actions that the application exports.

Flags: Write

The “application-id” property

  “application-id”           gchar *

The unique identifier for the application.

Flags: Read / Write / Construct

Default value: NULL

The “flags” property

  “flags”                    GApplicationFlags

Flags specifying the behaviour of the application.

Flags: Read / Write

The “inactivity-timeout” property

  “inactivity-timeout”       guint

Time (ms) to stay alive after becoming idle.

Flags: Read / Write

Default value: 0

The “is-busy” property

  “is-busy”                  gboolean

Whether the application is currently marked as busy through g_application_mark_busy() or g_application_bind_busy_property().

Flags: Read

Default value: FALSE

Since 2.44

The “is-registered” property

  “is-registered”            gboolean

If g_application_register() has been called.

Flags: Read

Default value: FALSE

The “is-remote” property

  “is-remote”                gboolean

If this application instance is remote.

Flags: Read

Default value: FALSE

The “resource-base-path” property

  “resource-base-path”       gchar *

The base resource path for the application.

Flags: Read / Write

Default value: NULL

The “activate” signal

void
user_function (GApplication *application,
               gpointer      user_data)

The ::activate signal is emitted on the primary instance when an activation occurs. See g_application_activate().

Flags: Run Last

The “command-line” signal

gint
user_function (GApplication            *application,
               GApplicationCommandLine *command_line,
               gpointer                 user_data)

The ::command-line signal is emitted on the primary instance when a commandline is not handled locally. See g_application_run() and the GApplicationCommandLine documentation for more information.

Flags: Run Last

The “handle-local-options” signal

gint
user_function (GApplication *application,
               GVariantDict *options,
               gpointer      user_data)

The ::handle-local-options signal is emitted on the local instance after the parsing of the commandline options has occurred.

You can add options to be recognised during commandline option parsing using g_application_add_main_option_entries() and g_application_add_option_group().

Signal handlers can inspect options (along with values pointed to from the arg_data of an installed GOptionEntrys) in order to decide to perform certain actions, including direct local handling (which may be useful for options like --version).

In the event that the application is marked G_APPLICATION_HANDLES_COMMAND_LINE the "normal processing" will send the option dictionary to the primary instance where it can be read with g_application_command_line_get_options(). The signal handler can modify the dictionary before returning, and the modified dictionary will be sent.

In the event that G_APPLICATION_HANDLES_COMMAND_LINE is not set, "normal processing" will treat the remaining uncollected command line arguments as filenames or URIs. If there are no arguments, the application is activated by g_application_activate(). One or more arguments results in a call to g_application_open().

If you want to handle the local commandline arguments for yourself by converting them to calls to g_application_open() or g_action_group_activate_action() then you must be sure to register the application first. You should probably not call g_application_activate() for yourself, however: just return -1 and allow the default handler to do it for you. This will ensure that the --gapplication-service switch works properly (i.e. no activation in that case).

Note that this signal is emitted from the default implementation of local_command_line(). If you override that function and don't chain up then this signal will never be emitted.

You can override local_command_line() if you need more powerful capabilities than what is provided here, but this should not normally be required.

Flags: Run Last

Since 2.40

The “open” signal

void
user_function (GApplication *application,
               gpointer      files,
               gint          n_files,
               gchar        *hint,
               gpointer      user_data)

The ::open signal is emitted on the primary instance when there are files to open. See g_application_open() for more information.

Flags: Run Last

The “shutdown” signal

void
user_function (GApplication *application,
               gpointer      user_data)

The ::shutdown signal is emitted only on the registered primary instance immediately after the main loop terminates.

Flags: Run Last

The “startup” signal

void
user_function (GApplication *application,
               gpointer      user_data)

The ::startup signal is emitted on the primary instance immediately after registration. See g_application_register().

Flags: Run First