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 mes-
     sage, 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