rmvq(9F)

NAME | SYNOPSIS | INTERFACE LEVEL | PARAMETERS | DESCRIPTION | CONTEXT | EXAMPLES | SEE ALSO | WARNINGS | NOTES

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 message (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	freezestr(q); 
 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	unfreezestr(q);

SEE ALSO

freemsg(9F), freezestr(9F), getq(9F), insq(9F), unfreezestr(9F)

Writing Device Drivers

STREAMS Programming Guide

WARNINGS

Make sure that the message mp is linked onto q to avoid a possible system panic.

NOTES

The stream must be frozen using freezestr(9F) before calling rmvq( ).

SunOS 5.8  Last Revised 28 Jan 1993

NAME | SYNOPSIS | INTERFACE LEVEL | PARAMETERS | DESCRIPTION | CONTEXT | EXAMPLES | SEE ALSO | WARNINGS | NOTES