sys/ipc.h — XSI interprocess communication access structure
[XSI] #include <sys/ipc.h>
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.
Mode bits:
- IPC_CREAT
- Create entry if key does not exist.
- IPC_EXCL
- Fail if key exists.
- IPC_NOWAIT
- Error if request would need to wait.
Keys:
- IPC_PRIVATE
- Private key.
Control commands:
- IPC_RMID
- Remove identifier.
- IPC_SET
- Set options.
- IPC_STAT
- Get options.
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);
None.
None.
None.
XSH ftok
First released in Issue 2. Derived from System V Release 2.0.
This reference page is clarified with respect to macros and symbolic constants.
The description of IPC_NOWAIT is updated to eliminate the use of "must".
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