settings:
    parent, serial number 1
    in = -1, out = 4
settings:
    parent, serial number 2
    in = 5, out = -1
settings:
    child, serial number 1
    in = 3, out = -1
settings:
    child, serial number 2
    in = -1, out = 6
printed by child thread serial number 1: greetings from parent thread serial number 1: we are process 4223 thread ID 1000b6000 1000b6000
printed by parent thread serial number 2: greetings from child thread serial number 2: we are process 4225 thread ID 100281000 100281000