--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/usr/src/cmd/mailx/lock.c	Tue Jun 02 18:56:50 2009 +0900
@@ -0,0 +1,55 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License, Version 1.0 only
+ * (the "License").  You may not use this file except in compliance
+ * with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
+/*	  All Rights Reserved  	*/
+
+
+/*
+ * University Copyright- Copyright (c) 1982, 1986, 1988
+ * The Regents of the University of California   
+ * All Rights Reserved
+ *
+ * University Acknowledgment- Portions of this document are derived from
+ * software developed by the University of California, Berkeley, and its
+ * contributors.
+ */
+
+#pragma ident	"@(#)lock.c	1.15	05/06/08 SMI"
+
+/*
+ * lock a file pointer
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <fcntl.h>
+
+int
+lock(FILE *fp, char *mode, int blk)
+{
+	struct flock	l;
+
+	l.l_type = !strcmp(mode, "r") ? F_RDLCK : F_WRLCK;
+	l.l_whence = 0;
+	l.l_start = l.l_len = 0L;
+	return fcntl(fileno(fp), blk ? F_SETLKW : F_SETLK, &l);
+}