Path: utzoo!attcan!uunet!mstan!frank
From: frank@Morgan.COM (Frank Wortner)
Newsgroups: comp.os.minix
Subject: atexit() for Minix 1.3
Keywords: atexit(), Minix
Message-ID: <114@mstan.Morgan.COM>
Date: 15 Nov 88 01:33:45 GMT
Reply-To: frank@Morgan.COM (Frank Wortner)
Organization: Morgan Stanley and Co., NY, NY
Lines: 69

I've written an atexit() function for use with the Minix 1.3 library.
It's occasionally useful, and no one (that I can recall) has posted
anything like it yet, so here it is.  Enjoy!

					Frank
------------------------------------------------------------------------------
echo x - atexit.doc
sed '/^X/s///' > atexit.doc << '/'
Xint atexit(func)
Xvoid (*func)();
X
Xatexit() arranges for the subroutine whose address is func to be
Xcalled upon normal program termination.  atexit() returns zero
Xif the registration cannot be made, non-zero otherwise.
/
echo x - atexit.c
sed '/^X/s///' > atexit.c << '/'
X/* Copyright 1988 Frank Wortner
X**	You may reproduce and use this software as long as you
X**	do not delete this notice from the source code.
X*/
X
X#define MAXFN 33	/* Maximum number of functions registerable
X			   (includes 1 for __cleanup)			*/
X
Xtypedef void (*PFN)();	/* Pointer to FuNction */
X
Xextern PFN __cleanup;	/* imported from exit.c */
X
Xstatic PFN fn[MAXFN];	/* addresses of functions stored here */
Xstatic int nfn = -1;	/* number of functions registered less one */
X
Xvoid checkcleanup(), run_atexit();
X
Xint atexit(fun)
XPFN fun;
X{
X	if (nfn == -1)			/* Do we need to check for stdio? */
X		checkcleanup();
X	if (nfn >= MAXFN)		/* Run out of room yet? */
X		return (-1);
X	fn[++nfn] = fun;		/* Save the address of the subr. */
X	return (0);
X}
X
X/* Check to see if stdio is used.  If yes register stdio's cleanup routine
X** with the atexit() system and then force stdio to call run_atexit().
X*/
Xstatic void checkcleanup()
X{
X	if (__cleanup)			/* stdio used ? */
X		fn[++nfn] = __cleanup;
X	__cleanup = run_atexit;
X}
X
X/* Run the requested subroutines */
Xstatic void run_atexit()
X{
X	while (nfn >= 0) {
X		(*fn)[nfn--]();
X	}
X}
/


-- 
						Frank

"Computers are mistake amplifiers."