illumos: manual page: unlinkb.9f

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 }