Manual Pages for UNIX Operating System command usage for man wr

Kernel Functions for Drivers                               WR(9F)



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

SYNOPSIS
     #include 
     #include 



     queue_t *WR(queue_t *q);


INTERFACE LEVEL
     Architecture independent level 1 (DDI/DKI).

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


DESCRIPTION
     The WR() function accepts a read queue pointer as  an  argu-
     ment  and  returns  a pointer to the write queue of the same
     module.


     CAUTION: Make sure  the  argument  to  this  function  is  a
     pointer to a read queue. WR() will not check for queue type,
     and a system panic could result if the pointer is not  to  a
     read queue.

RETURN VALUES
     The pointer to the write queue.

CONTEXT
     The WR() function can be called  from  user,  interrupt,  or
     kernel context.

EXAMPLES
     Example 1 Using WR()


     In a STREAMS close(9E) routine,  the  driver  or  module  is
     passed a pointer to the read queue. These usually are set to
     the address of the module-specific data  structure  for  the
     minor device.



       1   xxxclose(q, flag)
       2       queue_t *q;



SunOS 5.11          Last change: 16 Jan 2006                    1






Kernel Functions for Drivers                               WR(9F)



       3       int flag;
       4   {
       5             q->q_ptr = NULL;
       6         WR(q)->q_ptr = NULL;
                     . . .
       7   }


SEE ALSO
     close(9E), OTHERQ(9F), RD(9F)


     Writing Device Drivers


     STREAMS Programming Guide







































SunOS 5.11          Last change: 16 Jan 2006                    2