Awesome
background
Issue any function call in a background thread.
Caveats
- you must compile with
--gc:arcor--gc:orc - you must compile with
--threads:on - due to Nim bugs, your function declaration must specify types for all parameters.
Usage
Prefix your function call with background to immediately run it in a
background thread. The return value may be invoked to retrieve any result
of the call.
import background
proc greet(): int =
echo "hello"
result = 42
var greeting = background greet() # run greet() in background
assert greeting() == 42 # recover any return value
echo greeting() # it's still 42, buddy
Here's a slightly more interesting example from the tests in which we make three expensive calls in the background and recover their results.
# we'll use this to track when threads terminate
var q {.global.}: int
# our "expensive" call
proc fib(n: int; o: int = 0): int =
result =
case n
of 0, 1:
1
else:
fib(n-1) + fib(n-2)
# tracking termination order
if o > 0:
q.inc o
let
x = 44 # 3rd most expensive
y = 46 # most expensive
z = 45 # 2nd most expensive
var a = background fib(x)
checkpoint "a: created background invocation"
var b = background fib(y, o = 3)
checkpoint "b: created background invocation"
var c = background fib(z, 2)
checkpoint "c: created background invocation"
checkpoint "waiting for results..."
checkpoint "a: return value ", a()
check a() == 1134903170
check q == 0
checkpoint "b: return value ", b()
check b() == 2971215073
check q == 5
checkpoint "c: return value ", c()
check c() == 1836311903
check q == 5
The output from the tests looks like this:
Installation
$ nimph clone disruptek/background
or if you're still using Nimble like it's 2012,
$ nimble install https://github.com/disruptek/background
Documentation
License
MIT