This function demarshals a value from a string. This function calls g_value_init() on the @value argument, so it need not be initialised beforehand. This function can handle char, uchar, boolean, int, uint, long, ulong, enum, flags, float, double, string, GdkColor, GdkRGBA and GtkAdjustment type values. Support for GtkWidget type values is still to come. Upon errors %FALSE will be returned and @error will be assigned a GError from the GTK_BUILDER_ERROR domain.