/** @file  ../include/sys/ipc.h

 @internalComponent

 */

 /** @fn  ftok(const char *pathname, int proj_id)

 @param pathname

 @param proj_id

 @return   The ftok function will return -1 if pathname does not exist or if it cannot be accessed by the calling process.

 On  success  the  generated key_t value is returned.

   The ftok function attempts to create a unique key suitable for use with the msgget , semget and shmget functions given the pathname of an existing file and a user-selectable id.

  The specified pathname must specify an existing file that is accessible to the calling process

 or the call will fail.

 Also, note that links to files will return the

 same key, given the same id.

 Examples:

 @code

 #include <sys/types.h>

 #include <sys/ipc.h>

 #include <stdio.h>

 int main(void)

 {

     char *pathame = "C:\XXX";

     int proj_id = 100;

     key_t fkey;

     if ((fkey = ftok(pathame, proj_id)) == -1) {

         printf("ftok() failed

 ");

     }

     return 0;

 }

 @endcode

 @see semget()

 @see shmget()

 @see msgget()

 @capability Deferred @ref RFs::Entry(const TDesC16&, TEntry&)

 @publishedAll

 @externallyDefinedApi

 */

 /** @struct ipc_perm

 To store information needed in determining  permissions  to  perform  an  ipc  operation.

 @publishedAll

 @externallyDefinedApi

 */

 /** @var ipc_perm::cuid

 creator user id

 */

 /** @var ipc_perm::cgid

 creator group id 

 */

 /** @var ipc_perm::uid

 user id

 */

 /** @var ipc_perm::gid

 group id 

 */

 /** @var ipc_perm::mode

 rw permission

 */

 /** @var ipc_perm::seq

 sequence X (to generate unique ipcid)

 */

 /** @var ipc_perm::key

 user specified msg or sem or shm key

 */

 /** @def IPC_CREAT

 SVID required constants (same values as system 5). create entry if key does not exist.

 @publishedAll

 @externallyDefinedApi

 */

 /** @def IPC_EXCL

 SVID required constants (same values as system 5). fail if key exists.

 @publishedAll

 @externallyDefinedApi

 */

 /** @def IPC_NOWAIT

 SVID required constants (same values as system 5). error if request must wait.

 @publishedAll

 @externallyDefinedApi

 */

 /** @def IPC_PRIVATE	

 private key 

 @publishedAll

 @externallyDefinedApi

 */

 /** @def IPC_RMID

 remove identifier

 @publishedAll

 @externallyDefinedApi

 */

 /** @def IPC_SET

 set options

 @publishedAll

 @externallyDefinedApi

 */

 /** @def IPC_STAT

 get options

 @publishedAll

 @externallyDefinedApi

 */