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Name

Synopsis

void qwait( queue_t *q);

int qwait_sig( queue_t *q);

Interface Level

Solaris DDI specific (Solaris DDI).

Arguments

qp

Pointer to the queue that is being opened or closed.

Description

This can be viewed as there being an implicit wakeup when a thread leaves a put(9E) or srv(9E) procedure or after a qtimeout(9F) or qbufcall(9F) callback procedure has been run in the same perimeter.

qprocson(9F) must be called before calling qwait() or qwait_sig().

qwait() is not interrupted by a signal, whereas qwait_sig() is interrupted by a signal. qwait_sig() normally returns non-zero, and returns zero when the waiting was interrupted by a signal.

qwait() and qwait_sig() are similar to cv_wait() and cv_wait_sig() (see condvar(9F) ), except that the mutex is replaced by the inner and outer perimeters and the signalling is implicit when a thread leaves the inner perimeter.

Return Values

1. For qwait_sig(), indicates that the condition was not necessarily signaled and the function returned because a signal was pending.

Context

These functions can only be called from an open(9E) or close(9E) routine.

Examples

The open routine sends down a T_INFO_REQ message and waits for the T_INFO_ACK . The arrival of the T_INFO_ACK is recorded by resetting a flag in the unit structure (WAIT_INFO_ACK ).

The example assumes that the module is D_MTQPAIR or D_MTPERMOD .

xxopen(qp, ...)
    queue_t *qp;
{
    struct xxdata *xx;
    /* Allocate xxdata structure */
    qprocson(qp);
    /* Format T_INFO_ACK in mp */
    putnext(qp, mp);
    xx->xx_flags |= WAIT_INFO_ACK;
    while (xx->xx_flags & WAIT_INFO_ACK)
        qwait(qp);
    return (0);
}
xxrput(qp, mp)
    queue_t *qp;
    mblk_t *mp;
{
    struct xxdata *xx = (struct xxdata *)q->q_ptr;
    ...
    case T_INFO_ACK:
        if (xx->xx_flags & WAIT_INFO_ACK) {
            /* Record information from info ack */
            xx->xx_flags &= ~WAIT_INFO_ACK;
            freemsg(mp);
            return;
        }
    ...
}

See Also

Table of Contents

• Name
• Synopsis
• Interface Level
• Arguments
• Description
• Return Values
• Context
• Examples
• See Also