error = sosend(wso, (struct mbuf *)0, ap->a_uio, 0, (struct mbuf *)0, 0);
error = sosend(wso, NULL, ap->a_uio, NULL, NULL, 0);
fifo_write(v)	void *v;{	struct vop_write_args /* {		struct vnode *a_vp;		struct uio *a_uio;		int  a_ioflag;		struct ucred *a_cred;	} */ *ap = v;	struct socket *wso = ap->a_vp->v_fifoinfo->fi_writesock;	struct proc *p = ap->a_uio->uio_procp;	int error;#ifdef DIAGNOSTIC	if (ap->a_uio->uio_rw != UIO_WRITE)		panic("fifo_write mode");#endif	if (ap->a_ioflag & IO_NDELAY)		wso->so_state |= SS_NBIO;	VOP_UNLOCK(ap->a_vp, 0, p);	error = sosend(wso, (struct mbuf *)0, ap->a_uio, 0, (struct mbuf *)0, 0);	vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY, p);	if (ap->a_ioflag & IO_NDELAY)		wso->so_state &= ~SS_NBIO;	return (error);}