sys-intr(2) - Unix First Edition Manual Page
11/3/71SYS_INTR (II)

NAME intr -- set interrupt handling
SYNOPSIS sys intr; arg / intr = 27.
DESCRIPTION When arg is 0, interrupts (ASCII DELETE) are ignored. Whenarg is 1, interrupts cause their normal result, that is,

force an exit. When arg is a location within the program,control is transferred to that location when an interrupt occurs. After an interrupt is caught, it is possible to resumeexecution by means of an rti instruction; however, great care must be exercised, since all I/O is terminatedabruptly upon an interrupt. In particular, reads of the typewriter tend to return with 0 characters read, thussimulating an end of file.

BUGS It should be easier to resume after an interrupt, but Idon't know how to make it work.

OWNER ken, dmr