ftok(3)                    Library Functions Manual                    ftok(3)

NOME
       ftok - converte um caminho de diretorio e um identificador de projeto
       para uma chave IPC System V

BIBLIOTECA
       Biblioteca C Padrao (libc, -lc)

SINOPSE
       #include <sys/ipc.h>

       key_t ftok(const char *pathname, int proj_id);

DESCRICAO
       The ftok()  function uses the identity of the file named by the given
       pathname (which must refer to an existing, accessible file)  and the
       least significant 8 bits of proj_id (which must be nonzero) to generate
       a key_t type System V IPC key, suitable for use with msgget(2),
       semget(2), or shmget(2).

       The resulting value is the same for all pathnames that name the same
       file, when the same value of proj_id is used.  The value returned
       should be different when the (simultaneously existing) files or the
       project IDs differ.

VALOR DE RETORNO
       On success, the generated key_t value is returned.  On failure -1 is
       returned, with errno indicating the error as for the stat(2)  system
       call.

ATRIBUTOS
       Para uma explicacao dos termos usados nesta secao, consulte
       attributes(7).

       +--------------------------------------------+---------------+---------+
       |Interface                                   | Atributo      | Valor   |
       +--------------------------------------------+---------------+---------+
       |ftok()                                      | Thread safety | MT-Safe |
       +--------------------------------------------+---------------+---------+
PADROES
       POSIX.1-2008.

HISTORICO
       POSIX.1-2001.

NOTAS
       On some ancient systems, the prototype was:

           key_t ftok(char *pathname, char proj_id);

       Today, proj_id is an int, but still only 8 bits are used.  Typical
       usage has an ASCII character proj_id, that is why the behavior is said
       to be undefined when proj_id is zero.

       Of course, no guarantee can be given that the resulting key_t is
       unique.  Typically, a best-effort attempt combines the given proj_id
       byte, the lower 16 bits of the inode number, and the lower 8 bits of
       the device number into a 32-bit result.  Collisions may easily happen,
       for example between files on /dev/hda1 and files on /dev/sda1.

EXEMPLOS
       Veja semget(2).

VEJA TAMBEM
       msgget(2), semget(2), shmget(2), stat(2), sysvipc(7)

TRADUCAO
       A traducao para portugues brasileiro desta pagina man foi criada por
       Rubens de Jesus Nogueira <darkseid99@usa.net> e Andre Luiz Fassone
       <lonely_wolf@ig.com.br>

       Esta traducao e uma documentacao livre; leia a Licenca Publica Geral
       GNU Versao 3 <https://www.gnu.org/licenses/gpl-3.0.html> ou posterior
       para as condicoes de direitos autorais.  Nenhuma responsabilidade e
       aceita.

       Se voce encontrar algum erro na traducao desta pagina de manual, envie
       um e-mail para a lista de discussao de tradutores
       <debian-l10n-portuguese@lists.debian.org>.

Linux man-pages 6.06            31 outubro 2023                        ftok(3)