ftok(3) [freebsd man page]

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/types.h>
     #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 msgget(2), 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.

SEE ALSO

     msgget(2), semget(2), shmget(2)

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

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 exist-
     ing 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