MSGGET(S)                XENIX System V                 MSGGET(S)



     Name
          msgget - Gets message queue.

     Syntax
          #include <sys/types.h>
          #include <sys/ipc.h>
          #include <sys/msg.h>

          int msgget (key, msgflg)
          key_t key;
          int msgflg;

     Description
          msgget returns the message queue identifier associated with
          key.

          A message queue identifier, an associated message queue, and
          data structure (see intro(S)) are created for key if one of
          the following is true:

               key is equal to IPC_PRIVATE .

               key does not already have a message queue identifier
               associated with it, and (msgflg & IPC_CREAT ) is
               ``true''.

          Values for the data structure associated with the new
          message queue identifier are initialized as follows:

               msg_perm.cuid and msg_perm.uid are set equal to the
               effective user ID of the calling process.
               msg_perm.cgid and msg_perm.gid are set equal to the
               effective group ID of the calling process.

               The low-order 9 bits of msg_perm.mode are set equal to
               the low-order 9 bits of msgflg.

               msg_qnum,msg_lspid,msg_lrpid, and msg_rtime are set
               equal to 0.

               msg_ctime is set equal to the current time.

               msg_qbytes is set equal to the system limit.

          msgget fails if one or more of the following is true:

               A message queue identifier exists for key; however,
               operation permission as specified by the low-order 9
               bits of msgflg would not be granted (see intro(S)).
               [EACCES]

               A message queue identifier does not exist for key and



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     MSGGET(S)                XENIX System V                 MSGGET(S)



               (msgflg & IPC_CREAT ) is ``false''.  [ENOENT]

               A message queue identifier would be created but the
               system-imposed limit on the maximum number of allowed
               message queue identifiers for the system would be
               exceeded.  [ENOSPC]

               A message queue identifier exists for the key but (
               (msgflg & IPC_CREAT ) & (msgflg && IPC_EXCL ) ) is
               ``true''.  [EEXIST]

     Return Value
          Upon successful completion, the message queue identifier is
          returned.  This is a non-negative integer.  Otherwise, a
          value of -1 is returned and errno is set to indicate the
          error.

     See Also
          intro(S), msgctl(S), msgop(S).

     Notes
          Programs using this function must be compiled with the -Me
          compiler option.
































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