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.

ARGUMENTS

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 pertinent).

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