ftok(3) BSD Library Functions Manual ftok(3)
NAME
ftok -- create IPC identifier from path name
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <sys/ipc.h>
key_t
ftok(const char *path, int id);
DESCRIPTION
The ftok() function attempts to create a unique key suitable for use with
the semget(2), and shmget(2) functions, given the path of an existing
file and a user-selectable id.
The specified path must specify an existing file that is accessible to
the calling process or the call will fail. Also, note that links to
files will return the same key, given the same id.
RETURN VALUES
The ftok() function will return -1 if path does not exist or if it cannot
be accessed by the calling process.
LEGACY SYNOPSIS
#include <sys/types.h>
#include <sys/ipc.h>
The include file <sys/types.h> is necessary.
SEE ALSO
semget(2), shmget(2), compat(5)
HISTORY
The ftok() function originates with System V and is typically used by
programs that use the System V IPC routines.
AUTHORS
Thorsten Lockert <tholo@sigmasoft.com>
BUGS
The returned key is computed based on the device minor number and inode
of the specified path, in combination with the lower 8 bits of the given
id. Thus, it is quite possible for the routine to return duplicate keys.
BSD July 9, 2009 BSD
Mac OS X 10.8 - Generated Mon Aug 27 18:37:26 CDT 2012