Manual Pages for UNIX Operating System command usage for man awrite

Driver Entry Points                                    awrite(9E)



NAME
     awrite - asynchronous write to a device

SYNOPSIS
     #include 
     #include 
     #include 
     #include 
     #include 

     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  asyn-
     chronous  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




SunOS 5.11          Last change: 28 Mar 1997                    1






Driver Entry Points                                    awrite(9E)



     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(3C), 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 5.11          Last change: 28 Mar 1997                    2