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msgids(2) [opensolaris man page]

msgids(2)							   System Calls 							 msgids(2)

NAME
msgids - discover all message queue identifiers SYNOPSIS
#include <sys/msg.h> int msgids(int *buf, uint_t nids, uint_t *pnids); DESCRIPTION
The msgids() function copies all active message queue identifiers from the system into the user-defined buffer specified by buf, provided that the number of such identifiers is not greater than the number of integers the buffer can contain, as specified by nids. If the size of the buffer is insufficient to contain all of the active message queue identifiers in the system, none are copied. Whether or not the size of the buffer is sufficient to contain all of them, the number of active message queue identifiers in the system is copied into the unsigned integer pointed to by pnids. If nids is 0 or less than the number of active message queue identifiers in the system, buf is ignored. RETURN VALUES
Upon successful completion, msgids() returns 0. Otherwise, -1 is returned and errno is set to indicate the error. ERRORS
The msgids() function will fail if: EFAULT The buf or pnids argument points to an illegal address. USAGE
The msgids() function returns a snapshot of all the active message queue identifiers in the system. More may be added and some may be removed before they can be used by the caller. EXAMPLES
Example 1 msgids() example This is sample C code indicating how to use the msgids() function (see msgsnap(2)): void examine_queues() { int *ids = NULL; uint_t nids = 0; uint_t n; int i; for (;;) { if (msgids(ids, nids, &n) != 0) { perror("msgids"); exit(1); } if (n <= nids) /* we got them all */ break; /* we need a bigger buffer */ ids = realloc(ids, (nids = n) * sizeof (int)); } for (i = 0; i < n; i++) process_msgid(ids[i]); free(ids); } ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |MT-Level |Async-Signal-Safe | +-----------------------------+-----------------------------+ SEE ALSO
ipcrm(1), ipcs(1), Intro(2), msgctl(2), msgget(2), msgsnap(2), msgrcv(2), msgsnd(2), attributes(5) SunOS 5.11 8 Mar 2000 msgids(2)

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msgget(2)							   System Calls 							 msgget(2)

NAME
msgget - get message queue SYNOPSIS
#include <sys/msg.h> int msgget(key_t key, int msgflg); DESCRIPTION
The msgget() argument 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: o key is IPC_PRIVATE. o 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 message queue identifier is initialized as follows: o msg_perm.cuid, msg_perm.uid, msg_perm.cgid, and msg_perm.gid are set to the effective user ID and effective group ID, respec- tively, of the calling process. o The low-order 9 bits of msg_perm.mode are set to the low-order 9 bits of msgflg. o msg_qnum, msg_lspid, msg_lrpid, msg_stime, and msg_rtime are set to 0. o msg_ctime is set to the current time. o msg_qbytes is set to the system limit. See NOTES. RETURN VALUES
Upon successful completion, a non-negative integer representing a message queue identifier is returned. Otherwise, -1 is returned and errno is set to indicate the error. ERRORS
The msgget() function will fail if: 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. EEXIST A message queue identifier exists for key but (msgflg&IPC_CREAT) and (msgflg&IPC_EXCL) are both true. 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 identi- fiers system wide would be exceeded. See NOTES. ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Interface Stability |Standard | +-----------------------------+-----------------------------+ SEE ALSO
rctladm(1M), Intro(2), msgctl(2), msgrcv(2), msgsnd(2), setrctl(2), ftok(3C), attributes(5), standards(5) NOTES
The system-defined limit used to initialize msg_qbytes is the minimum enforced value of the calling process's process.max-msg-qbytes resource control. The system-imposed limit on the number of message queue identifiers is maintained on a per-project basis using the project.max-msg-ids resource control. The zone.max-msg-ids resource control restricts the total amount of message queue identifiers that can be allocated by a zone. See rctladm(1M) and setrctl(2) for information about using resource controls. SunOS 5.11 14 Aug 2006 msgget(2)
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