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

6       backq - get pointer to the queue behind the current queue
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SYNOPSIS

9       #include <sys/stream.h>
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13       queue_t *backq(queue_t *cq);
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INTERFACE LEVEL

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

20       cq    The  pointer  to the current queue.   queue_t is an alias for the
21             queue(9S) structure.
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DESCRIPTION

25       The backq() function returns a pointer to the queue preceding  cq  (the
26       current queue). If cq is a read queue, backq() returns a pointer to the
27       queue downstream from cq, unless it is the stream end. If cq is a write
28       queue,  backq()  returns  a pointer to the next queue upstream from cq,
29       unless it is the stream head.
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RETURN VALUES

32       If successful, backq() returns a pointer to  the  queue  preceding  the
33       current queue. Otherwise, it returns NULL.
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CONTEXT

36       The backq() function can be called from user, interrupt, or kernel con‐
37       text.
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SEE ALSO

40       queue(9S)
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43       Writing Device Drivers
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46       STREAMS Programming Guide
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50SunOS 5.11                        16 Jan 2006                        backq(9F)