All 4 Uses

function
in
American Sniper
(Edited)

I spent the whole first week of nav school frowning at a desk in front of a Toughbook laptop computer, learning the computer's functions, how to hook up to a GPS and manipulate the satellite imagery and maps.
p. 132.6 *

functions = computer code modules each of which perform a specific task
I never really believed the Iraqis would turn the country into a truly functioning democracy, but I thought at one point that there was a chance.
p. 221.5

functioning = working
There was no functioning government, and it was beyond lawless.
p. 285.3

functioning = properly working
The official government still wasn't functioning here, and the Iraqi police and army were nowhere near capable of keeping order, naturally.
p. 317.6 *

functioning = working or operating

Definitions:

(1) (function as in: Its main function is to...)
purpose, job, or natural activity
(2) (function as in: can't function well without sleep)
work or operate -- sometimes to work or operate normally or in a particular way
(3) (function as in: I'm attending a function tonight)
a social event or ceremony -- especially one attended for work or out of a sense of duty
(4) (function as in: oxygen is a function of altitude)
saying one results from another; or saying that the amount of one thing is dependent upon the value of another.

If x is a function of y, then x results from y; or the amount of x can be calculated based on the amount of y.
(5) (function as in: Amazon's new search function)
computer code that performs a specific task
(6) (function as in: a mathematical function)
a formula or mathematical expression that describes a relationship between variables
(7) (meaning too rare to warrant focus)
For more specialized meanings in math and chemistry, see a comprehensive dictionary.