##-
# Author: Brian Tiffin
# Dedicated to the public domain
#
# Date: November 2016
# Modified: 2016-12-01/01:04-0500
##+
#
# fork.icn, demonstrate process forking
#
procedure main()
    local sharedvar := 42

    # parent process
    i := fork() | stop("fork() fail")
    if i < 0 then stop("fork fail with ", i) 

    # at this point, two nearly identical processes are running
    # each will have a unique pid and "i" result
    # the variable "sharedvar" will be a copy. Both processes will
    # see it as 42 at first.  Child divides to 21, parent doubles to 84
    if i = 0 then {
        write("child process: ", right(i, 6), ", ", sharedvar)
        sharedvar /:= 2
    } else {
        write("parent process: ", right(i, 5), ", ", sharedvar)
        sharedvar *:= 2
    }
    # both processes will display this line and then end   
    write("sharedvar for ", if i = 0 then "child " else "parent",
          " process is now: ", sharedvar)
end