Nim/tests/stdlib/tuserlocks.nim

discard """
  matrix: "--threads:on"
"""

import std/rlocks

var r: RLock
r.initRLock()
doAssert r.tryAcquire()
doAssert r.tryAcquire()
r.release()
r.release()

block:
  var x = 12
  withRLock r:
    inc x
  doAssert x == 13

r.deinitRLock()