|mb_top||(Vt struct mbuf *) A pointer to the top of constructed mbuf chain.|
|mb_cur||(Vt struct mbuf *) A pointer to the currently filled mbuf.|
|(Vt int) Number of bytes left in the current mbuf.|
|(Vt int) Total number of bytes placed in the mbuf chain.|
|mb_copy||(Vt mb_copy_t *) User-defined function to perform a copy into mbuf; useful if any unusual data conversion is necessary.|
|(Vt void *) User-supplied data which can be used in the mb_copy function.|
mb_done function disposes an mbuf chain pointed to by mbp->mb_top field and sets the field to NULL.
mb_detach function returns the value of mbp->mb_top field and sets its value to NULL.
mb_fixhdr recalculates the length of an mbuf chain and updates the m_pkthdr.len field of the first mbuf in the chain. It returns the calculated length.
mb_reserve ensures that the object of the length specified by the size argument will fit in the current mbuf (mbuf allocation is performed if necessary), and advances all pointers as if the real data was placed. Returned value will point to the beginning of the reserved space. Note that the size of the object should not exceed MLEN bytes.
All mb_put_* functions perform an actual copy of the data into mbuf chain. Functions which have le or be suffixes will perform conversion to the little- or big-endian data formats.
mb_put_mem function copies size bytes of data specified by the source argument to an mbuf chain. The type argument specifies the method used to perform a copy, and can be one of the following:
|Use bcopy function.|
|MB_MUSER||Use copyin(9) function.|
|Use an "inline" loop which does not call any function.|
|MB_MZERO||Do not copy any data, but just fill the destination with zero bytes.|
|Call function specified by the mbp->mb_copy field.|
All int functions except mb_fixhdr return zero if successful and an error code otherwise.
Note: after failure of any function, an mbuf chain is left in the broken state, and only mb_done function can safely be called to destroy it.
struct mbchain *mbp; struct mbuf *m;
mb_init(mbp); mb_put_uint8(mbp, 33); mb_put_uint16le(mbp, length); m = m_copym(mbp->mb_top, 0, M_COPYALL, M_TRYWAIT); send(m); mb_done(mbp);
This manual page was written by
.An Boris Popov Aq bp@FreeBSD.org .
|February 20, 2001||MBCHAIN (9)|