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.
The <sys/ipc.h> header is used by three mechanisms for XSI interprocess communication (IPC): messages, semaphores, and shared memory. All use a common structure type, ipc_perm, to pass information used in determining permission to perform an IPC operation.
The <sys/ipc.h> header shall define the ipc_perm structure, which shall include the following members:
uid_t uid Owner's user ID. gid_t gid Owner's group ID. uid_t cuid Creator's user ID. gid_t cgid Creator's group ID. mode_t mode Read/write permission.
The <sys/ipc.h> header shall define the uid_t, gid_t, mode_t, and key_t types as described in <sys/types.h>.
The <sys/ipc.h> header shall define the following symbolic constants.
Create entry if key does not exist.
Fail if key exists.
Error if request must wait.
The following shall be declared as a function and may also be defined as a macro. A function prototype shall be provided.
key_t ftok(const char *, int);
The following sections are informative.
The System Interfaces volume of POSIX.1-2017, ftok()
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. 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.opengroup.org/unix/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 .
ftok(3p), semop(3p), sys_msg.h(0p), sys_sem.h(0p), sys_shm.h(0p).