RTEMS 4.9.3 On-Line Library

device_read() for Devices

RTEMS Filesystem Design Guide

6.4.4.3: device_read() for Devices

Corresponding Structure Element:

device_read()

Arguments:

rtems_libio_t     *iop,
void              *buffer,
unsigned32         count

File:

deviceio.c

Description:

This routine will extract the major and minor numbers for the device from the - jnode- associated with the file descriptor.

A rtems_io_read() call will be made to the device driver associated with the file descriptor. The major and minor device number will be sent as arguments as well as an argument list consisting of:

file control block
file position index
buffer pointer where the data read is to be placed
count indicating the number of bytes that the program wishes to read from the device
flags from the file control block

On return from the rtems_io_read() the number of bytes that were actually read will be returned to the calling program.

RTEMS Filesystem Design Guide