msgget(2) msgget(2) NAME msgget - get message queue SYNOPSIS #include <sys/msg.h> int msgget(key_t key, int msgflg); DESCRIPTION msgget() returns the message queue identifier associated with key. A message queue identifier and associated message queue and data structure are created for key if one of the following is true: key is equal to IPC_PRIVATE. This call creates a new identifier, subject to available resources. The identifier will never be returned by another call to msgget() until it has been released by a call to msgctl(). The identifier should be used among the calling process and its descendents; however, it is not a requirement. The resource can be accessed by any process having the proper permissions. key does not already have a message queue identifier associated with it, and (msgflg & IPC_CREAT) is ``true''. Upon creation, the data structure associated with the new message queue identifier is initialized as follows: msg_perm.cuid, msg_perm.uid, msg_perm.cgid, and msg_perm.gid are set equal to the effective user ID and effective group ID, respectively, 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, msg_stime, 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. RETURN VALUE 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. ERRORS msgget() fails if one or more of the following is true: Hewlett-Packard Company - 1 - HP-UX Release 10.20: July 1996 msgget(2) msgget(2) [EACCES] A message queue identifier exists for key, but operation permission 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 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) && (msgflg & IPC_EXCL)) is ``true''. SEE ALSO ipcrm(1), ipcs(1), msgctl(2), msgop(2), stdipc(3C). STANDARDS CONFORMANCE msgget(): SVID2, SVID3, XPG2, XPG3, XPG4 Hewlett-Packard Company - 2 - HP-UX Release 10.20: July 1996