write(9E) Driver Entry Points write(9E)NAMEwrite - 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 com‐
ponent of dev and the user credentials pointed to by cred_p, if perti‐
nent.
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 ALSOread(2), write(2), read(9E), physio(9F), cb_ops(9S), uio(9S)
Writing Device Drivers
SunOS 5.10 28 Mar 1997 write(9E)
