<sys/ipc.h> (original) (raw)
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 ipc_perm structure shall contain 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 uid_t, gid_t, mode_t, and key_t types shall be defined as described in <sys/types.h>.
Definitions shall be provided for the following constants:
Mode bits:
IPC_CREAT
Create entry if key does not exist.
IPC_EXCL
Fail if key exists.
IPC_NOWAIT
Error if request must 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);
The following sections are informative.
End of informative text.