watch


Description:

public unowned ExpressionWatch watch (Object? this_, owned ExpressionNotify notify)

Installs a watch for the given expression that calls the notify function whenever the evaluation of this may have changed.

GTK cannot guarantee that the evaluation did indeed change when the notify gets invoked, but it guarantees the opposite: When it did in fact change, the notify will be invoked.

Parameters:

this

a Expression

this_

the `this` argument to watch

notify

callback to invoke when the expression changes

user_data

user data to pass to notify callback

user_destroy

destroy notify for user_data

Returns:

The newly installed watch. Note that the only reference held to the watch will be released when the watch is unwatched which can happen automatically, and not just via unwatch. You should call @ref if you want to keep the watch around.