AREAD(9E)AREAD(9E)NAMEaread - asynchronous read from a device
aread(dev_t dev, struct aio_req *aio_reqp, cred_t *cred_p);
Solaris DDI specific (Solaris DDI). This entry point is optional.
Drivers that do not support an aread() entry point should use nodev(9F)PARAMETERS
Pointer to the aio_req(9S) structure that describes where
the data is to be stored.
Pointer to the credential structure.
The driver's aread() routine is called to perform an asynchronous read.
getminor(9F) can be used to access the minor number component of the
dev argument. aread() may use the credential structure pointed to by
cred_p to check for superuser access by calling drv_priv(9F). The
aread() routine may also examine the uio(9S) structure through the
aio_req structure pointer, aio_reqp. aread() 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.
The aread() routine should return 0 for success, or the appropriate
This function is called from user context only.
Example 1 The following is an example of an aread() routine:
xxaread(dev_t dev, struct aio_req *aio, cred_t *cred_p)
struct xxstate *xsp;
instance = getminor(dev);
xsp = ddi_get_soft_state(statep, instance);
/*Verify soft state structure has been allocated */
if (xsp == NULL)
return (aphysio(xxstrategy, anocancel,
dev, B_READ, xxminphys, aio));
SEE ALSOread(2), aioread(3C), awrite(9E), read(9E), strategy(9E), write(9E),
anocancel(9F), aphysio(9F), ddi_get_soft_state(9F), drv_priv(9F), get‐
minor(9F), minphys(9F), nodev(9F), aio_req(9S), cb_ops(9S), uio(9S)
Writing Device Drivers
There is no way other than calling aphysio(9F) to accomplish an asyn‐
Mar 28, 1997 AREAD(9E)