Does barley flour have to be cooked out like wheat flour?

It would need a bit of cooking time; taste as you go along. You can usually tell that it's done when the liquid gets to the desired thickness, which is 3-5 minutes, depending. I will use alternate flours to thicken a dish, matching the flour to the dish. For example, I will use cornmeal or masa to thicken chili; semolina to thicken a pasta sauce (unless I'm serving it over polenta, in which case I might use cornmeal); rice flour to thicken Indian and Chinese sauces. I don't care for the texture of cornstarch thickening in everything, so I mix it up a bit. Oat flour will jell quickly but can still taste raw unless you let it sit for a couple of minutes.
I add in the flours by "eyeball method" with no strict measurements.

I am using it as a thickener. I have recently replaced the white flour with 1 minute quick oats ground up in a powder. By just adding hot water it;s quickly absorbed. Now I want to also add barley flour to it also for an enhanced flavor but I can't locate an equivelant in powder form so I'm wondering if it requires an equal amount of cooking time that wheat flour needs to remove the uncooked flour taste.
Thanks for your response.

Can you describe what you are making; are you using it as a thickener in a sauce for example? I'm also not sure what you mean by the phrase "cooked out". Happy to help if you can clarify.