Function msgbuf_do_addchar

freebsd/kern/subr_msgbuf.c:149–160

 */

static void
msgbuf_do_addchar(struct msgbuf * const mbp, u_int * const seq, const int c)
{
	u_int pos;

	/* Make sure we properly wrap the sequence number. */
	pos = MSGBUF_SEQ_TO_POS(mbp, *seq);
	mbp->msg_cksum += (u_int)(u_char)c -
	    (u_int)(u_char)mbp->msg_ptr[pos];
	mbp->msg_ptr[pos] = c;
	*seq = MSGBUF_SEQNORM(mbp, *seq + 1);
}

/*
 * Append a character to a message buffer.