Subject: What is difference between SIGSEGV and SIGBUS
To: None <current-users@NetBSD.ORG>
From: Alex Barclay <>
List: current-users
Date: 08/02/1995 09:49:35
Just a quick question this one...

I have recently being trying to port spice3f4 to NetBSD, a pretty
easy port except for some confusion over signals.

What I would like to know is what is the correct definition of a
segmentation violation and a bus error.

My interpretation has been (up until now)

SEGV = Trying to access an address outside of those allocated to a

BUS = Trying to do something daft on a bus, e.g. trying to access an
odd location when the bus has no notion of an 8 bit access.

IF (said with caution) I am right then if I attempt to access an
address at a silly location outside of my address space do I get a
SIGBUS, becuase of the silly access; or a SIGSEGV because of the
outside of my address space?

Either way NetBSD-very-very-current seems to differ from historical
Berkeley Unix as I suppose that this part of SPICE used to work once.

Any thoughts?