signal callback delegate or function to connect
void callback(gio.app_info.AppInfo info, glib.variant.VariantG platformData, gio.app_launch_context.AppLaunchContext appLaunchContext)
info the #GAppInfo that is about to be launched (optional)
platformData additional platform-specific data for this launch (optional)
appLaunchContext the instance the signal is connected to (optional)
Yes.After to execute callback after default handler, No.After to execute before (default)
Signal ID
Connect to LaunchStarted signal.
The #GAppLaunchContext::launch-started signal is emitted when a #GAppInfo is about to be launched. If non-null the platform_data is an GVariant dictionary mapping strings to variants (ie a{sv}), which contains additional, platform-specific data about this launch. On UNIX, at least the startup-notification-id keys will be present.
The value of the startup-notification-id key (type s) is a startup notification ID corresponding to the format from the [startup-notification specification](https://specifications.freedesktop.org/startup-notification-spec/startup-notification-0.1.txt). It allows tracking the progress of the launchee through startup.
It is guaranteed that this signal is followed by either a #GAppLaunchContext::launched or #GAppLaunchContext::launch-failed signal.
Because a launch operation may involve spawning multiple instances of the target application, you should expect this signal to be emitted multiple times, one for each spawned instance.