# mailbox locking
exim -odi -f t1@foo userx
Subject: First

local_delivery
First message.
****
exim_lock -v test-mail/userx
exim -odi -f t1@foo userx
Subject: Second

local_delivery
Second message
****
exim -qf
****
exim_lock -v -fcntl test-mail/userx
exim -odi -f t2@foo userx
Subject: Third

local_delivery_fcntl
Third message
****
exim -qf
****
exim_lock -v -fcntl test-mail/userx
exim -odi -f t3@foo userx
Subject: Fourth

local_delivery_fcntl_blocking
Fourth message
****
exim -qf
****