write(9e) [opensolaris man page]

write(9E)							Driver Entry Points							 write(9E)

NAME

       write - write data to a device

SYNOPSIS

       #include <sys/types.h>
       #include <sys/errno.h>
       #include <sys/open.h>
       #include <sys/cred.h>
       #include <sys/ddi.h>
       #include <sys/sunddi.h>

       int prefixwrite(dev_t dev, struct uio *uio_p, cred_t *cred_p);

INTERFACE LEVEL

       Architecture independent level 1 (DDI/DKI). This entry point is optional.

PARAMETERS

       dev	  Device number.

       uio_p	  Pointer to the  uio(9S) structure that describes where the data is to be stored in user space.

       cred_p	  Pointer to the  user credential structure for the I/O transaction.

DESCRIPTION

       Used for character or raw data I/O, the driver  write() routine is called indirectly through  cb_ops(9S) by the	write(2) system call.  The
       write() routine supervises the data transfer from user space to a device described by the  uio(9S) structure.

       The  write() routine should check the validity of the minor number component of	dev and the user credentials pointed to by cred_p, if per-
       tinent.

RETURN VALUES

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

EXAMPLES

       The following is an example of a write() routine using physio(9F) to perform writes to a seekable device:

	 static int
	 xxwrite(dev_t dev, struct uio *uiop, cred_t *credp)
	 {
	       int instance;
	       xx_t	xx;

	       instance = getminor(dev);
	       xx = ddi_get_soft_state(xxstate, instance);
	       if (xx == NULL)
		      return (ENXIO);
	       return (physio(xxstrategy, NULL, dev, B_WRITE,
		      xxmin, uiop));
	 }

SEE ALSO

       read(2), write(2), read(9E), physio(9F), cb_ops(9S), uio(9S)

       Writing Device Drivers

SunOS 5.11							    28 Mar 1997 							 write(9E)

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)