Re: Segments

Michael S <already5chosen@yahoo.com> writes:

Not every system capable of running C supports signals.  I would
think that those that support signals are not even majority.

"man raise" tells me that raise() is C99.  "man signal" tells me that
signal() is C99.

Of those that do support signals, not every one supports catching
SIGSEGV.

"man 7 signal" tells me that SIGSEGV is P1990, i.e., 'the original
POSIX.1-1990 standard'.  I.e., there were even some Windows systems
that support it.

Of those that do support catching SIGSEGV, not every one can recover
after that.

Gforth catches and recovers from SIGSEGV in order to return to
Gforth's command line rather than terminating the process; in
snapshots from recent years that's also used for determining whether
some number is probably an address (try to read from that address; if
there's a signal, it's not an address).  I tried building Gforth on a
number of Unix systems, and even the most rudimentary ones (e.g.,
Ultrix), supported catching SIGSEGV.  There is a port to Windows with
Cygwin done by Bernd Paysan.  I don't know if that could catch
SIGSEGV, but I am sure that it's possible in Windows in some way, even
if that way is not available through Cygwin.

- anton
--
'Anyone trying for "industrial quality" ISA should avoid undefined behavior.'
  Mitch Alsup, <c17fcd89-f024-40e7-a594-88a85ac10d20o@googlegroups.com>