Meaning would reasonably have to be generated by individuals for it to be fulfilling, rather than to have one thrust upon you from outside yourself. As subjective as it may be, it's more realistic as to meaning in its essence rather than reducing us to a function, something teleological in a mechanical sense rather than a purpose which can be provisional and change as goals are met or priorities adjust.
My meaning of life is different than a meaning behind or underpinning life itself. The latter has no meaning, it merely has existence. Those who have the capacity to comprehend can discern that meaning is a motivator factor to actions and the will as well. Animals don't have a purpose to life, they serve functions as they experience life much faster in comparison and don't have the seeming ability to contemplate their life's meanings. They shouldn't, however, be reduced to a means, which is another thing entirely that connects to ethics more than whatever one might call the study of the meaning of life (teleology, perhaps?)