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ftok (3)

ftok (3) ( Solaris man: Библиотечные вызовы )

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ftok (3) ( Русские man: Библиотечные вызовы )

ftok (3) ( Linux man: Библиотечные вызовы )

ftok (3) ( POSIX man: Библиотечные вызовы )

BSD mandoc

NAME

ftok

 - create IPC identifier from path name

LIBRARY

Lb libc

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(3), semget(2) and shmget(2) functions given the Fa path of an existing file and a user-selectable Fa id .

The specified Fa 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 Fa id .

RETURN VALUES

The ftok ();
function will return -1 if Fa path does not exist or if it cannot be accessed by the calling process.

HISTORY

The ftok ();
function originates with System V and is typically used by programs that use the System V IPC routines.

AUTHORS

An Thorsten Lockert Aq tholo@sigmasoft.com

BUGS

The returned key is computed based on the device minor number and inode of the specified Fa path in combination with the lower 8 bits of the given Fa id . Thus it is quite possible for the routine to return duplicate keys.