Blocking interrupts prevents any interruption of the current process, including process-interrupt, process-kill, process-reset, process-break and process-stop. These interrupts are all queued and processed once interrupts become unblocked.
The effect of
stays in force until the next call to either current-process-unblock-interrupts or
, or an exit out of the scope of a surrounding allowing-block-interrupts or with-interrupts-blocked. Inside this range bodies of allowing-block-interrupts and with-interrupts-blocked have their own state, but they restore it on exit.
LispWorks User Guide and Reference Manual - 21 Dec 2011