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diff --git a/man-pages-posix-2013/man3p/ftok.3p b/man-pages-posix-2013/man3p/ftok.3p new file mode 100644 index 0000000..7b30e2e --- /dev/null +++ b/man-pages-posix-2013/man3p/ftok.3p @@ -0,0 +1,193 @@ +'\" et +.TH FTOK "3P" 2013 "IEEE/The Open Group" "POSIX Programmer's Manual" +.SH PROLOG +This manual page is part of the POSIX Programmer's Manual. +The Linux implementation of this interface may differ (consult +the corresponding Linux manual page for details of Linux behavior), +or the interface may not be implemented on Linux. + +.SH NAME +ftok +\(em generate an IPC key +.SH SYNOPSIS +.LP +.nf +#include <sys/ipc.h> +.P +key_t ftok(const char *\fIpath\fP, int \fIid\fP); +.fi +.SH DESCRIPTION +The +\fIftok\fR() +function shall return a key based on +.IR path +and +.IR id +that is usable in subsequent calls to +\fImsgget\fR(), +\fIsemget\fR(), +and +\fIshmget\fR(). +The application shall ensure that the +.IR path +argument is the pathname of an existing file that the process is +able to +\fIstat\fR(), +with the exception that if +\fIstat\fR() +would fail with +.BR [EOVERFLOW] +due to file size, +\fIftok\fR() +shall still succeed. +.P +The +\fIftok\fR() +function shall return the same key value for all paths that name the +same file, when called with the same +.IR id +value, and should return different key values when called with different +.IR id +values or with paths that name different files existing on the same +file system at the same time. It is unspecified whether +\fIftok\fR() +shall return the same key value when called again after the file named +by +.IR path +is removed and recreated with the same name. +.P +Only the low-order 8-bits of +.IR id +are significant. The behavior of +\fIftok\fR() +is unspecified if these bits are 0. +.SH "RETURN VALUE" +Upon successful completion, +\fIftok\fR() +shall return a key. Otherwise, +\fIftok\fR() +shall return (\fBkey_t\fP)\(mi1 and set +.IR errno +to indicate the error. +.SH ERRORS +The +\fIftok\fR() +function shall fail if: +.TP +.BR EACCES +Search permission is denied for a component of the path prefix. +.TP +.BR EIO +An error occurred while reading from the file system. +.TP +.BR ELOOP +A loop exists in symbolic links encountered during resolution of the +.IR path +argument. +.TP +.BR ENAMETOOLONG +.br +The length of a component of a pathname is longer than +{NAME_MAX}. +.TP +.BR ENOENT +A component of +.IR path +does not name an existing file or +.IR path +is an empty string. +.TP +.BR ENOTDIR +A component of the path prefix names an existing file that is neither +a directory nor a symbolic link to a directory, or the +.IR path +argument contains at least one non-\c +<slash> +character and ends with one or more trailing +<slash> +characters and the last pathname component names an existing file +that is neither a directory nor a symbolic link to a directory. +.P +The +\fIftok\fR() +function may fail if: +.TP +.BR ELOOP +More than +{SYMLOOP_MAX} +symbolic links were encountered during resolution of the +.IR path +argument. +.TP +.BR ENAMETOOLONG +.br +The length of a pathname exceeds +{PATH_MAX}, +or pathname resolution of a symbolic link produced an intermediate +result with a length that exceeds +{PATH_MAX}. +.LP +.IR "The following sections are informative." +.SH EXAMPLES +.SS "Getting an IPC Key" +.P +The following example gets a key based on the pathname +.BR /tmp +and the ID value +.IR a . +It also assigns the value of the resulting key to the +.IR semkey +variable so that it will be available to a later call to +\fIsemget\fR(), +\fImsgget\fR(), +or +\fIshmget\fR(). +.sp +.RS 4 +.nf +\fB +#include <sys/ipc.h> +\&... +key_t semkey; +.P +if ((semkey = ftok("/tmp", 'a')) == (key_t) -1) { + perror("IPC error: ftok"); exit(1); +} +.fi \fR +.P +.RE +.SH "APPLICATION USAGE" +For maximum portability, +.IR id +should be a single-byte character. +.P +Applications should not assume that the resulting key value is unique. +.SH RATIONALE +None. +.SH "FUTURE DIRECTIONS" +Future versions of this standard may add new interfaces to provide +unique keys. +.SH "SEE ALSO" +.IR "\fImsgget\fR\^(\|)", +.IR "\fIsemget\fR\^(\|)", +.IR "\fIshmget\fR\^(\|)" +.P +The Base Definitions volume of POSIX.1\(hy2008, +.IR "\fB<sys_ipc.h>\fP" +.SH COPYRIGHT +Portions of this text are reprinted and reproduced in electronic form +from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology +-- Portable Operating System Interface (POSIX), The Open Group Base +Specifications Issue 7, Copyright (C) 2013 by the Institute of +Electrical and Electronics Engineers, Inc and The Open Group. +(This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the +event of any discrepancy between this version and the original IEEE and +The Open Group Standard, the original IEEE and The Open Group Standard +is the referee document. The original Standard can be obtained online at +http://www.unix.org/online.html . + +Any typographical or formatting errors that appear +in this page are most likely +to have been introduced during the conversion of the source files to +man page format. To report such errors, see +https://www.kernel.org/doc/man-pages/reporting_bugs.html . |