value_is_fixed

function value_is_fixed(value:GObject.Value):Boolean {
    // Gjs wrapper for gst_value_is_fixed()
}

Tests if the given GValue, if available in a GstStructure (or any other container) contains a "fixed" (which means: one value) or an "unfixed" (which means: multiple possible values, such as data lists or data ranges) value.