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.\"	Changed data type of proj_id; minor fixes
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.TH FTOK 3 "11 abril 2020" GNU "Manual do Programador do Linux"
.SH NOME
ftok \- converte um caminho de diretório e um identificador de projeto para
uma chave IPC System V
.SH SINOPSE
.nf
\fB#include <sys/types.h>\fP
\fB#include <sys/ipc.h>\fP
.fi
.PP
\fBkey_t ftok(const char *\fP\fIpathname\fP\fB, int \fP\fIproj_id\fP\fB);\fP
.SH DESCRIÇÃO
The \fBftok\fP()  function uses the identity of the file named by the given
\fIpathname\fP (which must refer to an existing, accessible file)  and the
least significant 8 bits of \fIproj_id\fP (which must be nonzero) to generate a
\fIkey_t\fP type System V IPC key, suitable for use with \fBmsgget\fP(2),
\fBsemget\fP(2), or \fBshmget\fP(2).
.PP
The resulting value is the same for all pathnames that name the same file,
when the same value of \fIproj_id\fP is used.  The value returned should be
different when the (simultaneously existing) files or the project IDs
differ.
.SH "VALOR DE RETORNO"
On success, the generated \fIkey_t\fP value is returned.  On failure \-1 is
returned, with \fIerrno\fP indicating the error as for the \fBstat\fP(2)  system
call.
.SH ATRIBUTOS
Para uma explicação dos termos usados nesta seção, consulte
\fBattributes\fP(7).
.TS
allbox;
lb lb lb
l l l.
Interface	Atributo	Valor
T{
\fBftok\fP()
T}	Thread safety	MT\-Safe
.TE
.SH "DE ACORDO COM"
POSIX.1\-2001, POSIX.1\-2008.
.SH NOTAS
On some ancient systems, the prototype was:
.PP
.in +4n
.EX
\fBkey_t ftok(char *\fP\fIpathname\fP\fB, char \fP\fIproj_id\fP\fB);\fP
.EE
.in
.PP
Today, \fIproj_id\fP is an \fIint\fP, but still only 8 bits are used.  Typical
usage has an ASCII character \fIproj_id\fP, that is why the behavior is said to
be undefined when \fIproj_id\fP is zero.
.PP
Of course, no guarantee can be given that the resulting \fIkey_t\fP is unique.
Typically, a best\-effort attempt combines the given \fIproj_id\fP 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 \fI/dev/hda1\fP and files on \fI/dev/sda1\fP.
.SH EXEMPLOS
Veja \fBsemget\fP(2).
.SH "VEJA TAMBÉM"
\fBmsgget\fP(2), \fBsemget\fP(2), \fBshmget\fP(2), \fBstat\fP(2), \fBsysvipc\fP(7)
.SH COLOFÃO
Esta página faz parte da versão 5.10 do projeto Linux \fIman\-pages\fP. Uma
descrição do projeto, informações sobre relatórios de bugs e a versão mais
recente desta página podem ser encontradas em
\%https://www.kernel.org/doc/man\-pages/.
.PP
.SH TRADUÇÃO
A tradução para português brasileiro desta página man foi criada por
Rubens de Jesus Nogueira <darkseid99@usa.net>
e
André Luiz Fassone <lonely_wolf@ig.com.br>
.
.PP
Esta tradução é uma documentação livre; leia a
.UR https://www.gnu.org/licenses/gpl-3.0.html
Licença Pública Geral GNU Versão 3 
.UE
ou posterior para as condições de direitos autorais.
Nenhuma responsabilidade é aceita.
.PP
Se você encontrar algum erro na tradução desta página de manual,
envie um e-mail para
.MT debian-l10n-portuguese@lists.debian.org
a lista de discussão de tradutores
.ME .