##-
# Author: Brian Tiffin
# Dedicated to the public domain
#
# Date: August 2016
# Modified: 2016-10-03/22:59-0400
##+
#
# lock.icn, demonstrate mutual exclusive region locking
#
global x

procedure main()
    mx := mutex()
    x := 0
    t1 := thread incrementor(mx)
    t2 := thread incrementor(mx)
    every wait(t1 | t2)
    write("x = ", x)
end

procedure incrementor(m)
    lock(m)
    # a non atomic increment expression; fetch x,  add to x, store x
    x := x + 1
    unlock(m)
end