diff --git a/headers/posix/fcntl.h b/headers/posix/fcntl.h
index 190f38be7e..7b9e5fa8cf 100644
--- a/headers/posix/fcntl.h
+++ b/headers/posix/fcntl.h
@@ -1,64 +1,74 @@
+/* 
+** Distributed under the terms of the Haiku License.
+*/
 #ifndef _FCNTL_H
 #define _FCNTL_H
-/* 
-** Distributed under the terms of the OpenBeOS License.
-*/
+
 
 #include <sys/types.h>
 #include <sys/stat.h>
+#include <unistd.h>
 
-/* commands that can be passed to fcntl */
-#define	F_DUPFD			0x0001
-#define	F_GETFD			0x0002
-#define	F_SETFD			0x0004
-#define	F_GETFL			0x0008
-#define	F_SETFL			0x0010
-#define F_GETLK         0x0020
-#define F_RDLCK         0x0040
-#define F_SETLK         0x0080
-#define F_SETLKW        0x0100
-#define F_UNLCK         0x0200
-#define F_WRLCK         0x0400
 
-#define FD_CLOEXEC		1	/* Close on exec.  */
+/* commands that can be passed to fcntl() */
+#define	F_DUPFD			0x0001		/* duplicate fd */
+#define	F_GETFD			0x0002		/* get fd flags */
+#define	F_SETFD			0x0004		/* set fd flags */
+#define	F_GETFL			0x0008		/* get file status flags and access mode */
+#define	F_SETFL			0x0010		/* set file status flags */
+#define F_GETLK         0x0020		/* get locking information */
+#define F_RDLCK         0x0040		/* read or shared lock */
+#define F_SETLK         0x0080		/* set locking information */
+#define F_SETLKW        0x0100		/* as above, but waits if blocked */
+#define F_UNLCK         0x0200		/* unlock */
+#define F_WRLCK         0x0400		/* write or exclusive lock */
+
+/* file descriptor flags for fcntl() */
+#define FD_CLOEXEC		1			/* close on exec */
+
+/* file access modes for open() */
+#define O_RDONLY		0x0000		/* read only */
+#define O_WRONLY		0x0001		/* write only */
+#define O_RDWR			0x0002		/* read and write */
+#define O_ACCMODE   	0x0003		/* mask to get the access modes above */
+#define O_RWMASK		O_ACCMODE
 
 /* flags for open() */
-#define O_RDONLY		0	/* read only */
-#define O_WRONLY		1	/* write only */
-#define O_RDWR			2	/* read and write */
-#define O_RWMASK		3	/* Mask to get open mode */
+#define	O_EXCL			0x0100		/* exclusive creat */
+#define O_CREAT			0x0200		/* create and open file */
+#define O_TRUNC			0x0400		/* open with truncation */
+#define O_NOCTTY		0x1000		/* currently unsupported */
+#define	O_NOTRAVERSE	0x2000		/* do not traverse leaf link */
 
-#define O_CLOEXEC		0x0040	/* close fd on exec */
-#define	O_NONBLOCK		0x0080	/* non blocking io */
-#define	O_EXCL			0x0100	/* exclusive creat */
-#define O_CREAT			0x0200	/* create and open file */
-#define O_TRUNC			0x0400	/* open with truncation */
-#define O_APPEND		0x0800	/* to end of file */
-#define O_NOCTTY    	0x1000  /* currently unsupported */
-#define	O_NOTRAVERSE	0x2000	/* do not traverse leaf link */
-#define O_ACCMODE   	0x0003  /* currently unsupported */
-#define O_TEXT			0x4000	/* CR-LF translation	*/
-#define O_BINARY		0x8000	/* no translation	*/
+/* flags for open() and fcntl() */
+#define O_CLOEXEC		0x00000040	/* close on exec */
+#define	O_NONBLOCK		0x00000080	/* non blocking io */
+#define O_APPEND		0x00000800	/* to end of file */
+#define O_TEXT			0x00004000	/* CR-LF translation */
+#define O_BINARY		0x00008000	/* no translation */
+#define O_SYNC			0x00010000	/* write synchronized I/O file integrity */
+#define O_RSYNC			0x00020000	/* read synchronized I/O file integrity */
+#define O_DSYNC			0x00040000	/* write synchronized I/O data integrity */
 
-// currently not implemented additions:
-#define O_NOFOLLOW		0x00010000
+// ToDo: currently not implemented additions:
+#define O_NOFOLLOW		0x00080000
 	/* should we implement this? it's similar to O_NOTRAVERSE but will fail on symlinks */
-#define O_NOCACHE		0x00020000	/* doesn't use the file system cache if possible */
+#define O_NOCACHE		0x00100000	/* doesn't use the file system cache if possible */
 #define O_DIRECT		O_NOCACHE
-#define O_SHLOCK		0x00040000
-#define O_EXLOCK		0x00080000
-#define O_MOUNT			0x00100000	/* for file systems */
-#define O_FSYNC			0x10000000
+#define O_MOUNT			0x00200000	/* for file systems */
+#define O_TEMPORARY		0x00400000	/* used to avoid writing temporary files to disk */
+#define O_SHLOCK		0x01000000	/* obtain shared lock */
+#define O_EXLOCK		0x02000000	/* obtain exclusive lock */
 
 
 /* advisory file locking */
 
 struct flock {
-	short l_type;
-	short l_whence;
-	off_t l_start;
-	off_t l_len;
-	pid_t l_pid;
+	short	l_type;
+	short	l_whence;
+	off_t	l_start;
+	off_t	l_len;
+	pid_t	l_pid;
 };
 
 #define	LOCK_SH		0x01	/* shared file lock */