NAME

read − read data from a device

SYNOPSIS

#include <sys/types.h>
#include <sys/errno.h>
#include <sys/open.h>
#include <sys/uio.h>
#include <sys/cred.h>
#include <sys/ddi.h>
#include <sys/sunddi.h>
int prefixread(dev_t dev, uio ∗uio_p
, cred_t ∗cred_p);

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 cred(9S) user credential structure for the I/O transaction. 

INTERFACE LEVEL

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

DESCRIPTION

The driver read() routine is called indirectly through cb_ops(9S) by the read(2) system call.  The read() routine should check the validity of the minor number component of dev and the user credentials contained in the cred(9S) structure pointed to by cred_p (if pertinent).  The read() routine should supervise the data transfer into the user space described by the uio(9S) structure. 

RETURN VALUES

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

SEE ALSO

read(2), write(9E), cb_ops(9S), cred(9S), uio(9S)

SunOS 5.1  —  Last change: 11 Apr 1991