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From: darrylo@hpsrla.HP.COM (Darryl Okahata)
Newsgroups: comp.sys.ibm.pc
Subject: Re: signal() for Turbo C
Message-ID: <2670002@hpsrla.HP.COM>
Date: Sun, 23-Aug-87 17:10:31 EDT
Article-I.D.: hpsrla.2670002
Posted: Sun Aug 23 17:10:31 1987
Date-Received: Wed, 26-Aug-87 05:29:38 EDT
References: <1009@bsu-cs.UUCP>
Organization: Network Measurements Div - Santa Rosa, CA
Lines: 42

In comp.sys.ibm.pc, dhesi@bsu-cs.UUCP (Rahul Dhesi) writes:

> #! /bin/sh
> # This is a shell archive, meaning:
> # 1. Remove everything above the #! /bin/sh line.
> # 2. Save the resulting text in a file.
> # 3. Execute the file with /bin/sh (not csh) to create:
> #	signal.c
> #	signal.man
> # This will give you the C source and the manual for an implementation
> # of signal() for Turbo C.  Only SIGINT is currently recognized.
> #
  [ ... ]

     Thanks to Rahul Dhesi for writing this!  However, there are little
"gotchas" that one has to be careful of:

     1. Any routine called through the handler set up by the ctrlbreak()
	call uses the stack given to it by DOS.  The handler does not set
	up a stack before calling the specified routine.  It *appears* that
	the stack used is the one that was being used when the DOS function
	that was called was interrupted.  Because of this, there may or
	may not be enough room on the stack for the ctrl-break handler to
	properly run (there may not be enough room for local variables,
	recursive calls, etc.).

     2. As the stack that is being used may not be the one that Turbo C
	uses, the Turbo C program may terminate if stack overflow checking
	is turned on.

In my case, a TSR (Chris Dunford's PCED) was doing some processing when I
hit CTRL-C.  Because PCED sets up a local stack and because I had turned on
stack overflow checking in my Turbo C program, the Turbo C program was
aborting with a "stack overflow" error upon entry to main_handler().

     -- Darryl Okahata
	UUCP: { hplabs!hpcea, hpfcla }!hpsrla!darrylo
	CompuServe: 75206,3074

Disclaimer: the above is the author's personal opinion and is not the
opinion or policy of his employer or of the little green men that
have been following him all day.