WR(9f) - osol9

1WR(9F)                   Kernel Functions for Drivers                   WR(9F)
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NAME

6       WR, wr - get pointer to the write queue for this module or driver
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SYNOPSIS

9       #include <sys/stream.h>
10       #include <sys/ddi.h>
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14       queue_t *WR(queue_t *q);
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INTERFACE LEVEL

18       Architecture independent level 1 (DDI/DKI).
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PARAMETERS

21       q    Pointer to the read queue whose write queue is to be returned.
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DESCRIPTION

25       The  WR()  function  accepts  a  read  queue pointer as an argument and
26       returns a pointer to the write queue of the same module.
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29       CAUTION: Make sure the argument to this function is a pointer to a read
30       queue.  WR()  will  not  check for queue type, and a system panic could
31       result if the pointer is not to a read queue.
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RETURN VALUES

34       The pointer to the write queue.
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CONTEXT

37       The WR() function can be called from user, interrupt,  or  kernel  con‐
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EXAMPLES

41       Example 1 Using WR()
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44       In  a  STREAMS  close(9E)  routine,  the  driver  or module is passed a
45       pointer to the read queue. These usually are set to the address of  the
46       module-specific data structure for the minor device.
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50         1   xxxclose(q, flag)
51         2       queue_t *q;
52         3       int flag;
53         4   {
54         5             q->q_ptr = NULL;
55         6         WR(q)->q_ptr = NULL;
56                       . . .
57         7   }
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