msgget(2)                                                            msgget(2)



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 IPCPRIVATE.

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

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

          msgperm.cuid, msgperm.uid, msgperm.cgid, and msgperm.gid are set
          to the effective user ID and effective group ID, respectively, of
          the calling process.

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

          msgqnum, msglspid, msglrpid, msgstime, and msgrtime are set to
          0.

          msgctime is set to the current time.

          msgqbytes 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&IPCCREAT) is false.






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msgget(2)                                                            msgget(2)



     ENOSPC         A message queue identifier is to be created 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&IPCCREAT) and (msgflg&IPCEXCL) 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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