89 lines
2.1 KiB
Plaintext
89 lines
2.1 KiB
Plaintext
.if n .pH ddi.rm/d3/gen/putctl @(#)putctl 43.11 of 11/30/92
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.\" Copyright 1992, 1991 UNIX System Laboratories, Inc.
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.TH putctl D3
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.IX "\f4putctl\fP(D3)"
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.SH NAME
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\f4putctl\f1 \- send a control message to a queue
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.SH SYNOPSIS
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.nf
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.na
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.ft 4
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#include <sys/stream.h>
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#include <sys/ddi.h>
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.sp 0.4
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int putctl(queue_t *\f2q\fP, int \f2type\fP);
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.ft 1
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.ad
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.fi
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.SS Arguments
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.RS 0
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.IP "\f2q\f1" 10n
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Pointer to the queue to which the message is to be sent.
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.IP "\f2type\f1" 10n
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Message type (must be a control type).
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.RE
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.SH DESCRIPTION
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\f4putctl\f1 tests the \f2type\f1 argument
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to make sure a data type has not been specified,
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and then attempts to allocate a message block.
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\f4putctl\f1 fails if \f2type\f1
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is \f4M_DATA\f1, \f4M_PROTO\f1, or \f4M_PCPROTO\f1,
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or if a message block cannot be allocated.
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If successful, \f4putctl\f1 calls the \f4put\f1(D2) routine
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of the queue pointed to by \f2q\f1,
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passing it the allocated message.
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.SS "Return Values"
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On success, 1 is returned.
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Otherwise, if \f2type\f1 is a data type,
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or if a message block cannot be allocated,
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0 is returned.
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.SS Level
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Base or Interrupt.
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.SS "Synchronization Constraints"
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Does not sleep.
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.P
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Driver-defined basic locks, read/write locks, and sleep locks
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may not be held across calls to this function.
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.SS Examples
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The \f4send_ctl\f1 routine is used to pass control messages downstream.
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\f4M_BREAK\f1 messages are handled with \f4putctl\f1 (line 9).
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\f4putctl1\f1 (line 11) is used for \f4M_DELAY\f1 messages,
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so that \f2param\f1 can be
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used to specify the length of the delay.
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If an invalid message type is detected, \f4send_ctl\f1 returns 0, indicating failure
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(line 13).
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.sp 0.4
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.nf
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.ft 4
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.ps -1
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.vs -2
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1 int
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2 send_ctl(wrq, type, param)
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3 queue_t *wrq;
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4 uchar_t type;
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5 uchar_t param;
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6 {
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.sp 0.4
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7 switch (type) {
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8 case M_BREAK:
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9 return(putctl(wrq->q_next, M_BREAK));
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.sp 0.4
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10 case M_DELAY:
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11 return(putctl1(wrq->q_next, M_DELAY, param));
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.sp 0.4
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12 default:
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13 return(0);
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14 }
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15 }
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.vs
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.ps
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.ft 1
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.fi
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.IX "\f4putctl\fP(D3), example"
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.IX "\f4putctl1\fP(D3), example"
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.SH REFERENCES
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.na
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\f4put\fP(D2),
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\f4putctl1\fP(D3)
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.ad
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