MSGGET(2-SVR4)      RISC/os Reference Manual       MSGGET(2-SVR4)



NAME
     msgget - get message queue

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

     int msgget(keyt key, int msgflg);

DESCRIPTION
     msgget returns the message queue identifier associated with
     key.

     A message queue identifier and associated message queue and
     data structure [see intro(2)] are created for key if one of
     the following are true:

          key is IPC_PRIVATE.

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

     On creation, the data structure associated with the new mes-
     sage queue identifier is initialized as follows:

          msg_perm.cuid, msg_perm.uid, msg_perm.cgid, and
          msg_perm.gid are set to the effective user ID and
          effective group ID, respectively, of the calling pro-
          cess.

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

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

          msg_ctime is set to the current time.

          msg_qbytes is set to the system limit.

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

     EACCES         A message queue identifier exists for key,
                    but operation permission [see intro(2)] as
                    specified by the low-order 9 bits of msgflg
                    would not be granted.

     ENOENT         A message queue identifier does not exist for
                    key and (msgflg&IPC_CREAT) is false.

     ENOSPC         A message queue identifier is to be created



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MSGGET(2-SVR4)      RISC/os Reference Manual       MSGGET(2-SVR4)



                    but the system-imposed limit on the maximum
                    number of allowed message queue identifiers
                    system wide would be exceeded.

     EEXIST         A message queue identifier exists for key but
                    (msgflg&IPC_CREAT) and (msgflg&IPC_EXCL) are
                    both true.

SEE ALSO
     intro(2), msgctl(2), msgop(2), stdipc(3C).

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








































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