Emitted to convert the users input into a double value.
The signal handler is expected to use [method@Gtk.Editable.get_text] to retrieve the text of the spinbutton and set @new_value to the new value.
The default conversion uses g_strtod().
%TRUE for a successful conversion, %FALSE if the input was not handled, and %GTK_INPUT_ERROR if the conversion failed.
See Implementation
Emitted to convert the users input into a double value.
The signal handler is expected to use [method@Gtk.Editable.get_text] to retrieve the text of the spinbutton and set @new_value to the new value.
The default conversion uses g_strtod().