unlinkb(9f) [opensolaris man page]

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

NAME

       unlinkb - remove a message block from the head of a message

SYNOPSIS

       #include <sys/stream.h>

       mblk_t *unlinkb(mblk_t *mp);

INTERFACE LEVEL

       Architecture independent level 1 (DDI/DKI).

PARAMETERS

       mp    Pointer to the message.

DESCRIPTION

       The  unlinkb()  function removes the first message block from the message pointed to by mp. A new message, minus the removed message block,
       is returned.

RETURN VALUES

       If successful, the unlinkb() function returns a pointer to the message with the first message block removed. If there is only  one  message
       block in the message, NULL is returned.

CONTEXT

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

EXAMPLES

       Example 1 unlinkb() example

       The  routine  expects  to  get  passed  an M_PROTO T_DATA_IND message. It will remove and free the  M_PROTO header and return the remaining
       M_DATA portion of the message.

	 1  mblk_t *
	 2  makedata(mp)
	 3	mblk_t *mp;
	 4  {
	 5    mblk_t *nmp;
	 6
	 7    nmp = unlinkb(mp);
	 8    freeb(mp);
	 9    return(nmp);
	 10 }

SEE ALSO

       linkb(9F)

       Writing Device Drivers

       STREAMS Programming Guide

SunOS 5.11							    16 Jan 2006 						       unlinkb(9F)

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

NAME

       rmvb - remove a message block from a message

SYNOPSIS

       #include <sys/stream.h>

       mblk_t *rmvb(mblk_t *mp, mblk_t *bp);

INTERFACE LEVEL

       Architecture independent level 1 (DDI/DKI).

PARAMETERS

       mp	Message from which a block is to be removed. mblk_t is an instance of the
		 msgb(9S) structure.

       bp	Message block to be removed.

DESCRIPTION

       rmvb()  removes	a  message  block  (bp) from a message (mp), and returns a pointer to the altered message. The message block is not freed,
       merely removed from the message. It is the module or driver's responsibility to free the message block.

RETURN VALUES

       If successful, a pointer to the message (minus the removed block) is returned. The pointer is  NULL if bp was the only block of the message
       before
	rmvb() was called. If the designated message block (bp) does not exist, -1 is returned.

CONTEXT

       rmvb() can be called from user or interrupt context.

EXAMPLES

       This  routine  removes  all zero-length M_DATA message blocks from the given message.  For each message block in the message, save the next
       message block (line 10). If the current message block is of type M_DATA and has no data in its buffer (line 11), then remove  it  from  the
       message (line 12) and free it (line 13). In either case, continue with the next message block in the message (line 16).

	1  void
	2  xxclean(mp)
	3      mblk_t *mp;
	4  {
	5	   mblk_t *tmp;
	6	   mblk_t *nmp;
	7
	8	   tmp = mp;
	9	   while (tmp) {
       10		    nmp = tmp->b_cont;
       11		    if ((tmp->b_datap->db_type == M_DATA) &&
				  (tmp->b_rptr == tmp->b_wptr)) {
       12			 (void) rmvb(mp, tmp);
       13			 freeb(tmp);
       14		    }
       15		    tmp = nmp;
       16	   }
       17  }

SEE ALSO

       freeb(9F), msgb(9S)

       Writing Device Drivers

       STREAMS Programming Guide

SunOS 5.10							    11 Apr 1991 							  rmvb(9F)