rmvq(9r)rmvq(9r)NAME
rmvq - STREAMS: Removes a message block from a queue
SYNOPSIS
#include <sys/stream.h>
void rmvq(
queue_t *queue_pointer,
MBLKP message_to_be_removed );
ARGUMENTS
Specifies a pointer to the queue that contains the message block to be removed. The typedef queue_t is an alternate name for struct
queue_entry *. Specifies a pointer to the message block to be removed. The typedef MBLKP is an alternate name for typedef struct msgb *.
DESCRIPTION
The rmvq interface removes a message block from a queue. You can remove a message block from anywhere on a queue. To prevent modules and
drivers from having to deal with the internals of message linking on a queue, you can call either rmvq or getq to remove a message block
from a queue.
CAUTIONS
Make sure the message block pointer you pass to the message_to_be_removed argument exists to avoid a possible system panic.
RETURN VALUES
None
SEE ALSO
Kernel Interfaces: getq(9r), rmvb(9r)rmvq(9r)
Check Out this Related Man Page
rmvq(9F) Kernel Functions for Drivers rmvq(9F)NAME
rmvq - remove a message from a queue
SYNOPSIS
#include <sys/stream.h>
void rmvq(queue_t *q, mblk_t *mp);
INTERFACE LEVEL
Architecture independent level 1 (DDI/DKI).
PARAMETERS
q Queue containing the message to be removed.
mp Message to remove.
DESCRIPTION
rmvq() removes a message from a queue. A message can be removed from anywhere on a queue. To prevent modules and drivers from having to
deal with the internals of message linkage on a queue, either rmvq() or getq(9F) should be used to remove a message from a queue.
CONTEXT
rmvq() can be called from user or interrupt context.
EXAMPLES
This code fragment illustrates how one may flush one type of message from a queue. In this case, only M_PROTO T_DATA_IND messages are
flushed. For each message on the queue, if it is an M_PROTO message (line 8) of type T_DATA_IND (line 10), save a pointer to the next mes-
sage (line 11), remove the T_DATA_IND message (line 12) and free it (line 13). Continue with the next message in the list (line 19).
1 mblk_t *mp, *nmp;
2 queue_t *q;
3 union T_primitives *tp;
4
5 /* Insert code here to protect queue and message block */
6 mp = q->q_first;
7 while (mp) {
8 if (mp->b_datap->db_type == M_PROTO) {
9 tp = (union T_primitives *)mp->b_rptr;
10 if (tp->type == T_DATA_IND) {
11 nmp = mp->b_next;
12 rmvq(q, mp);
13 freemsg(mp);
14 mp = nmp;
15 } else {
16 mp = mp->b_next;
17 }
18 } else {
19 mp = mp->b_next;
20 }
21 }
22 /* End of region that must be protected */
When using rmvq(), you must ensure that the queue and the message block is not modified by another thread at the same time. You can achieve
this either by using STREAMS functions or by implementing your own locking.
SEE ALSO freemsg(9F), getq(9F), insq(9F)
Writing Device Drivers
STREAMS Programming Guide
WARNINGS
Make sure that the message mp is linked onto q to avoid a possible system panic.
SunOS 5.10 9 Jul 2001 rmvq(9F)