debian man page for qbufcall

qbufcall(9F)						   Kernel Functions for Drivers 					      qbufcall(9F)

NAME
       qbufcall - call a function when a buffer becomes available

SYNOPSIS
       #include <sys/stream.h>
       #include <sys/ddi.h>

       bufcall_id_t qbufcall(queue_t *q, size_t size, uint_t pri, void(*func)(void *arg), void *arg);

INTERFACE LEVEL
       Solaris DDI specific (Solaris DDI).

PARAMETERS
       q	       Pointer to STREAMS queue structure.

       size	       Number of bytes required for the buffer.

       pri	       Priority of the allocb(9F) allocation request (not used).

       func	       Function or driver routine to be called when a buffer becomes available.

       arg	       Argument to the function to be called when a buffer becomes available.

DESCRIPTION
       qbufcall()  serves as a qtimeout(9F) call of indeterminate length. When a buffer allocation request fails, qbufcall() can be used to sched-
       ule the routine func to be called with the argument arg when a buffer becomes available. func may call allocb()	or  it	may  do  something
       else.

       The  qbufcall() function is tailored to be used with the enhanced STREAMS framework interface, which is based on the concept of perimeters.
       (See mt-streams(9F).) qbufcall() schedules the specified function to execute after entering the perimeters associated with the queue passed
       in  as  the first parameter to qbufcall(). All outstanding timeouts and bufcalls must be cancelled (using, respectively, quntimeout(9F) and
       qunbufcall(9F)) before a driver close routine can block and before the close  routine calls qprocsoff(9F).

       qprocson(9F) must be called before calling either qbufcall() or qtimeout(9F).

RETURN VALUES
       If successful, qbufcall() returns a qbufcall ID that can be used in a call to qunbufcall(9F) to	cancel	the  request.  If  the	qbufcall()
       scheduling fails, func is never called and 0 is returned.

CONTEXT
       qbufcall() can be called from user or interrupt context.

SEE ALSO
       allocb(9F), mt-streams(9F), qprocson(9F), qtimeout(9F), qunbufcall(9F), quntimeout(9F)

       Writing Device Drivers

       STREAMS Programming Guide

WARNINGS
       Even  when  func  is called by qbufcall(), allocb(9F) can fail if another module or driver had allocated the memory before func was able to
       call allocb(9F).

SunOS 5.10							    17 Oct 2002 						      qbufcall(9F)