msgsys(2)                  DG/UX 4.30                   msgsys(2)



     NAME
          msgsys - Perform a message queue operation.

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

          int   msgsys  (P1, P2, P3, P4, P5, P6)
          int           P1;
          int           P2;
          int           P3;
          int           P4;
          int           P5;
          int           P6;

     PARAMETERS
          P1             An argument which indicates the type of
                         operation to be performed with message
                         queues. (0 - MSGGET, 1 - MSGCTL, 2 - MSGRCV,
                         3 - MSGSND)


          P2             If the operation is MSGGET, P2 is equal to
                         the message queue key. Otherwise, P2 is equal
                         to the message queue id.


          P3             If the operation is MSGGET, P3 equals to the
                         flags which indicate whether to create the
                         queue or not and the permissions for the
                         queue. If the operation is MSGCTL, P3 equals
                         to the control command number which specifies
                         the type of control command to perform.  If
                         the operation is MSGSND or MSGRCV, P3 equals
                         to the pointer to the message to be sent or
                         received.


          P4             If the operation is MSGGET, P4 is invalid. In
                         case of MSGCTL P4 is a pointer to a buffer
                         containig information about the message
                         queue. In case of MSGSND and MSGRCV, P4 is
                         equal to the size of the message's text
                         portion.


          P5             If the operation is MSGGET or MSGCTL, P5 is
                         invalid.  In case of MSGRCV P5 is equal to
                         the message type.  In case of MSGSND P5 is
                         equal to the message flags modifying the
                         message MSGSND operation.



     Licensed material--property of copyright holder(s)         Page 1

     msgsys(2)                  DG/UX 4.30                   msgsys(2)



          P6             If the operation is MSGRCV, P6 is equal to
                         the message flags modifying the MSGRCV
                         operation. Otherwise P6 is invalid.

     DESCRIPTION
          Msgsys() performs a message operation (MSGGET, MSGCTL,
          MSGSND, MSGRCV) indicated by the value of <P1>.

     ACCESS CONTROL
          See the description of the exception condition EACCES below.

     RETURN VALUE
          <msqid>        A non-negative integer that identifies the
                         message queue associated with <key>, returned
                         by msgget()


          0              Msgsnd,msgrcv or msgctl calls were
                         successful.


          -1             An error occurred.  Errno is set to indicate
                         the error.

     EXCEPTIONS
          The error codes returned depend on the type of message queue
          operations performed and are described in msgget(),
          msgctl(), msgsnd(), msgrcv().


          EINVAL         <P1> argument is not in the range of 0
                         through 3.

     SEE ALSO
          The related system calls:  msgget, msgctl, msgrcv, msgsnd.
          The related manual section:  intro(2).



















     Licensed material--property of copyright holder(s)         Page 2