XENIX <-> ULTRIX interrupts & traps

Chuck Forsberg WA7KGX caf at omen.UUCP
Fri Nov 14 05:36:49 AEST 1986


In article <43 at samira.UUCP> mike at samira.UUCP (Mike Deutsch) writes:
:Under XENIX, when the program returns from the interrupt handler, the
:program doesn't still expect to be reading at the read where the interrupt
:trap was received.  Under ULTRIX, it does.
 ....
:2)  I'd prefer the program to function as it does under XENIX.  How can
:I get it to not continue with the read when there was an interrupt during
:the read?

A longjmp from within the interrupt handler should do the trick.  When 4.2 BSD
changed the way signals affected read calls, thus breaking rb/sb, I changed
the interrupt handler from the previous no-op (just let the read fail) to a
longjmp.  Just make sure the longjmp always has a valid place to long jump to!

Chuck Forsberg WA7KGX Author of Pro-YAM communications Tools for PCDOS and Unix
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