awrite(9E)							Driver Entry Points							awrite(9E)

NAME

       awrite - asynchronous write to a device

SYNOPSIS

       #include <sys/uio.h>
       #include <sys/aio_req.h>
       #include <sys/cred.h>
       #include <sys/ddi.h>
       #include <sys/sunddi.h>

       intprefixawrite(dev_t dev, struct aio_req *aio_reqp, cred_t *cred_p);

INTERFACE LEVEL

       Solaris	DDI  specific  (Solaris  DDI).	This  entry  point  is	optional.  Drivers that do not support an  awrite() entry point should use
       nodev(9F)

PARAMETERS

       dev	       Device number.

       aio_reqp        Pointer to the  aio_req(9S) structure that describes where the data is stored.

       cred_p	       Pointer to the  credential structure.

DESCRIPTION

       The driver's awrite() routine is called to perform an asynchronous write. getminor(9F) can be used to  access the minor number component of
       the  dev argument. awrite() may use the	credential structure pointed to by  cred_p to check for superuser access by calling  drv_priv(9F).
       The  awrite() routine may also examine the  uio(9S) structure through  the   aio_req  structure	pointer,   aio_reqp.  awrite()	must  call
       aphysio(9F) with the aio_req pointer and a pointer to the driver's strategy(9E) routine.

       No fields of the uio(9S) structure pointed to by aio_req, other than uio_offset or uio_loffset, may be modified for non-seekable devices.

RETURN VALUES

       The  awrite() routine should return   0 for success, or the appropriate error number.

CONTEXT

       This function is called from user context only.

EXAMPLES

       Example 1: Using the awrite routine:

       The following is an example of an  awrite() routine:

       static int
       xxawrite(dev_t dev, struct aio_req *aio, cred_t *cred_p)
       {
	       int instance;
	       struct xxstate *xsp;

	       instance = getminor(dev);
	       xsp = ddi_get_soft_state(statep, instance);
	       /*Verify soft state structure has been allocated */
	       if (xsp == NULL)
			return (ENXIO);
	       return (aphysio(xxstrategy, anocancel, dev, B_WRITE, xxminphys, aio));
       }

SEE ALSO

       write(2),  aiowrite(3AIO),  aread(9E), read(9E), strategy(9E), write(9E), anocancel(9F), aphysio(9F), ddi_get_soft_state(9F), drv_priv(9F),
       getminor(9F), minphys(9F), nodev(9F), aio_req(9S), cb_ops(9S), uio(9S)

       Writing Device Drivers

BUGS

       There is no way other than calling aphysio(9F) to accomplish an asynchronous write.

SunOS 5.10							    28 Mar 1997 							awrite(9E)