##-
# Author: Brian Tiffin
# Dedicated to the public domain
#
# Date: October 2016
# Modified: 2016-10-08/19:22-0400
##+
#
# condvar.icn, demonstrate a threading condition variable
#

# taken from the Programming with Unicon book, page 146
procedure main()
    mtx := mutex()
    L := mutex([], mtx)
    cv := condvar(mtx)
    p := thread produce(L, cv)
    c := thread consume(L, cv)
    every wait(p | c)
end

procedure produce(L, cv)
    every put(L, !10) & *L=1 & signal(cv)
end

procedure consume(L, cv)
    i := 0
    while i < 10 do
        if x := get(L) then
             i +:= 1 & write(x)
        else
            critical cv: until *L>0 do wait(cv)
end