Add _Exit(3) as per C99. Discussed with espie@ some time ago.

src/include/stdlib.h

@@ -1,4 +1,4 @@
-/*	$OpenBSD: stdlib.h,v 1.29 2004/01/21 19:50:39 millert Exp $	*/
+/*	$OpenBSD: stdlib.h,v 1.30 2004/05/03 17:21:13 millert Exp $	*/
 /*	$NetBSD: stdlib.h,v 1.25 1995/12/27 21:19:08 jtc Exp $	*/
 
 /*-
@@ -111,6 +111,7 @@ void	*calloc(size_t, size_t);
 div_t	 div(int, int);
 char	*ecvt(double, int, int *, int *);
 __dead void	 exit(int);
+__dead void	 _Exit(int);
 char	*fcvt(double, int, int *, int *);
 void	 free(void *);
 char	*gcvt(double, int, char *);

src/lib/libc/stdlib/Makefile.inc

@@ -10,7 +10,7 @@ SRCS+=	a64l.c abort.c atexit.c atoi.c atof.c atol.c atoll.c bsearch.c \
 	setenv.c strtod.c strtol.c strtoll.c strtonum.c strtoul.c strtoull.c \
 	system.c \
 	tfind.c tsearch.c _rand48.c drand48.c erand48.c jrand48.c lcong48.c \
-	lrand48.c mrand48.c nrand48.c seed48.c srand48.c qabs.c qdiv.c
+	lrand48.c mrand48.c nrand48.c seed48.c srand48.c qabs.c qdiv.c _Exit.c
 
 .if   (${MACHINE_ARCH} == "m68k")
 SRCS+=	abs.S div.c labs.c ldiv.c
@@ -45,6 +45,7 @@ MAN+=	a64l.3 abort.3 abs.3 alloca.3 atexit.3 atof.3 atoi.3 atol.3 atoll.3 \
 	qdiv.3 qsort.3 radixsort.3 rand48.3 rand.3 random.3 realpath.3 \
 	strtod.3 strtonum.3 strtol.3 strtoul.3 system.3 tsearch.3
 
+MLINKS+=exit.3 _Exit.3
 MLINKS+=ecvt.3 fcvt.3 ecvt.3 gcvt.3
 MLINKS+=getenv.3 setenv.3 getenv.3 unsetenv.3 getenv.3 putenv.3
 MLINKS+=getopt_long.3 getopt_long_only.3

src/lib/libc/stdlib/_Exit.c

@@ -0,0 +1,26 @@
+/*	$OpenBSD: _Exit.c,v 1.1 2004/05/03 17:21:13 millert Exp $	*/
+
+/*
+ * Placed in the public domain by Todd C. Miller on January 21, 2004.
+ */
+
+#if defined(LIBC_SCCS) && !defined(lint)
+static char *rcsid = "$OpenBSD: _Exit.c,v 1.1 2004/05/03 17:21:13 millert Exp $";
+#endif /* LIBC_SCCS and not lint */
+
+#include <stdlib.h>
+#include <unistd.h>
+
+/*
+ * _Exit() is the ISO/ANSI C99 equivalent of the POSIX _exit() function.
+ * No atexit() handlers are called and no signal handlers are run.
+ * Whether or not stdio buffers are flushed or temporary files are removed
+ * is implementation-dependent.  As such it is safest to *not* flush
+ * stdio buffers or remove temporary files.  This is also consistent
+ * with most other implementations.
+ */
+void
+_Exit(int status)
+{
+	_exit(status);
+}

src/lib/libc/stdlib/exit.3

@@ -29,25 +29,30 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.\"	$OpenBSD: exit.3,v 1.9 2003/06/02 20:18:37 millert Exp $
+.\"	$OpenBSD: exit.3,v 1.10 2004/05/03 17:21:13 millert Exp $
 .\"
-.Dd June 29, 1991
+.Dd January 21, 2004
 .Dt EXIT 3
 .Os
 .Sh NAME
-.Nm exit
+.Nm exit, _Exit
 .Nd perform normal program termination
 .Sh SYNOPSIS
 .Fd #include <stdlib.h>
 .Ft void
 .Fn exit "int status"
+.Ft void
+.Fn _Exit "int status"
 .Sh DESCRIPTION
 The
 .Fn exit
-function terminates a process.
+and
+.Fn _Exit
+functions terminate a process.
 .Pp
-Before termination it performs the following functions in the
-order listed:
+Before termination,
+.Fn exit
+performs the following operations in the order listed:
 .Bl -enum -offset indent
 .It
 Call the functions registered with the
@@ -63,9 +68,25 @@ Unlink all files created with the
 function.
 .El
 .Pp
-Following this,
+The
+.Fn _Exit
+function terminates without calling the functions registered with the
+.Xr atexit 3
+function.
+The
+.Ox
+implementation of
+.Fn _Exit
+does not flush open output streams or unlink files created with the
+.Xr tmpfile 3
+function.
+However, this behavior is implementation-specific.
+.Pp
+Lastly,
 .Fn exit
-calls
+and
+.Fn _Exit
+call
 .Xr _exit 2 .
 Note that typically
 .Xr _exit 2
@@ -75,7 +96,9 @@ on to the parent, thus negative values have less meaning.
 .Sh RETURN VALUES
 The
 .Fn exit
-function never returns.
+and
+.Fn _Exit
+functions never return.
 .Sh SEE ALSO
 .Xr _exit 2 ,
 .Xr atexit 3 ,
@@ -85,5 +108,7 @@ function never returns.
 .Sh STANDARDS
 The
 .Fn exit
-function conforms to
-.St -ansiC .
+and
+.Fn _Exit
+functions conform to
+.St -ansiC-99 .