diff --git a/ChangeLog b/ChangeLog
index d912ecf014..41429478e9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+1999-02-18  Ulrich Drepper  <drepper@cygnus.com>
+
+	* io/Makefile (routines): Add lock64.
+	* io/Versions: Add lockf64 for GLIBC_2.1.1.
+	* sysdeps/generic/lockf64.c: New file.
+
 1999-02-16  Ulrich Drepper  <drepper@cygnus.com>
 
 	* string/bits/string2.h: Only use strncmp optimization if count
diff --git a/io/Makefile b/io/Makefile
index 9f08476248..9dccdb96df 100644
--- a/io/Makefile
+++ b/io/Makefile
@@ -1,4 +1,4 @@
-# Copyright (C) 1992, 93, 94, 95, 96, 97, 98 Free Software Foundation, Inc.
+# Copyright (C) 1992, 93, 94, 95, 96, 97, 98, 99 Free Software Foundation, Inc.
 # This file is part of the GNU C Library.
 
 # The GNU C Library is free software; you can redistribute it and/or
@@ -35,7 +35,7 @@ routines :=							      \
 	statvfs fstatvfs statvfs64 fstatvfs64			      \
 	umask chmod fchmod mkdir				      \
 	open open64 close read write lseek lseek64 access euidaccess  \
-	fcntl flock lockf					      \
+	fcntl flock lockf lockf64				      \
 	dup dup2 pipe						      \
 	creat creat64						      \
 	chdir fchdir						      \
diff --git a/io/Versions b/io/Versions
index 7892eebd0a..d816d03f07 100644
--- a/io/Versions
+++ b/io/Versions
@@ -80,4 +80,8 @@ libc {
     # s*
     statfs64; statvfs; statvfs64;
   }
+  GLIBC_2.1.1 {
+    # l*
+    lockf64;
+  }
 }
diff --git a/sysdeps/generic/lockf64.c b/sysdeps/generic/lockf64.c
new file mode 100644
index 0000000000..074dd7d82a
--- /dev/null
+++ b/sysdeps/generic/lockf64.c
@@ -0,0 +1,75 @@
+/* Copyright (C) 1994, 1996, 1997, 1998, 1999 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Library General Public License as
+   published by the Free Software Foundation; either version 2 of the
+   License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#include <sys/types.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <string.h>
+
+/* lockf is a simplified interface to fcntl's locking facilities.  */
+
+int
+lockf64 (int fd, int cmd, off64_t len64)
+{
+  struct flock fl;
+  off_t len = (off_t) len64;
+
+  if (len64 != (off64_t) len)
+    /* We can't represent the length.  */
+    return EOVERFLOW;
+
+  memset ((char *) &fl, '\0', sizeof (fl));
+
+  /* lockf is always relative to the current file position.  */
+  fl.l_whence = SEEK_CUR;
+  fl.l_start = 0;
+  fl.l_len = len;
+
+  switch (cmd)
+    {
+    case F_TEST:
+      /* Test the lock: return 0 if FD is unlocked or locked by this process;
+	 return -1, set errno to EACCES, if another process holds the lock.  */
+      if (__fcntl (fd, F_GETLK, &fl) < 0)
+	return -1;
+      if (fl.l_type == F_UNLCK || fl.l_pid == __getpid ())
+	return 0;
+      __set_errno (EACCES);
+      return -1;
+
+    case F_ULOCK:
+      fl.l_type = F_UNLCK;
+      cmd = F_SETLK;
+      break;
+    case F_LOCK:
+      fl.l_type = F_WRLCK;
+      cmd = F_SETLKW;
+      break;
+    case F_TLOCK:
+      fl.l_type = F_WRLCK;
+      cmd = F_SETLK;
+      break;
+
+    default:
+      __set_errno (EINVAL);
+      return -1;
+    }
+
+  return __fcntl (fd, cmd, &fl);
+}