<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<HTML
><HEAD
><TITLE
>parport_read</TITLE
><META
NAME="GENERATOR"
CONTENT="Modular DocBook HTML Stylesheet Version 1.7"><LINK
REL="HOME"
TITLE="The Linux 2.4 Parallel Port Subsystem"
HREF="book1.html"><LINK
REL="UP"
TITLE=" Linux parallel port driver API reference
"
HREF="a950.html"><LINK
REL="PREVIOUS"
TITLE="parport_write"
HREF="r1739.html"><LINK
REL="NEXT"
TITLE="parport_set_timeout"
HREF="r1833.html"></HEAD
><BODY
CLASS="REFENTRY"
BGCOLOR="#FFFFFF"
TEXT="#000000"
LINK="#0000FF"
VLINK="#840084"
ALINK="#0000FF"
><DIV
CLASS="NAVHEADER"
><TABLE
SUMMARY="Header navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TH
COLSPAN="3"
ALIGN="center"
>The Linux 2.4 Parallel Port Subsystem</TH
></TR
><TR
><TD
WIDTH="10%"
ALIGN="left"
VALIGN="bottom"
><A
HREF="r1739.html"
ACCESSKEY="P"
><<< Previous</A
></TD
><TD
WIDTH="80%"
ALIGN="center"
VALIGN="bottom"
></TD
><TD
WIDTH="10%"
ALIGN="right"
VALIGN="bottom"
><A
HREF="r1833.html"
ACCESSKEY="N"
>Next >>></A
></TD
></TR
></TABLE
><HR
ALIGN="LEFT"
WIDTH="100%"></DIV
><H1
><A
NAME="AEN1786"
></A
><SPAN
CLASS="phrase"
><SPAN
CLASS="PHRASE"
>parport_read</SPAN
></SPAN
></H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN1790"
></A
><H2
>Name</H2
>parport_read -- read a block of data from a parallel port
</DIV
><DIV
CLASS="REFSYNOPSISDIV"
><A
NAME="AEN1793"
></A
><H2
>Synopsis</H2
><DIV
CLASS="FUNCSYNOPSIS"
><A
NAME="AEN1795"
></A
><P
></P
><P
><CODE
><CODE
CLASS="FUNCDEF"
>ssize_t <TT
CLASS="FUNCTION"
>parport_read </TT
></CODE
>(struct parport * <TT
CLASS="PARAMETER"
><I
>port</I
></TT
>, void * <TT
CLASS="PARAMETER"
><I
>buffer</I
></TT
>, size_t <TT
CLASS="PARAMETER"
><I
>len</I
></TT
>);</CODE
></P
><P
></P
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN1805"
></A
><H2
>Arguments</H2
><P
></P
><DIV
CLASS="VARIABLELIST"
><DL
><DT
><TT
CLASS="PARAMETER"
><I
>port</I
></TT
></DT
><DD
><P
> port to read from
</P
></DD
><DT
><TT
CLASS="PARAMETER"
><I
>buffer</I
></TT
></DT
><DD
><P
> data buffer (in kernel space)
</P
></DD
><DT
><TT
CLASS="PARAMETER"
><I
>len</I
></TT
></DT
><DD
><P
> number of bytes of data to transfer
</P
></DD
></DL
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN1823"
></A
><H2
>Description</H2
><P
> This will read up to <TT
CLASS="PARAMETER"
><I
>len</I
></TT
> bytes of <TT
CLASS="PARAMETER"
><I
>buffer</I
></TT
> to the port
specified, using the IEEE 1284 transfer mode most recently
negotiated to (using <TT
CLASS="FUNCTION"
>parport_negotiate</TT
>), as long as that
mode supports reverse transfers (peripheral to host).
</P
><P
> It is the caller's responsibility to ensure that the first
<TT
CLASS="PARAMETER"
><I
>len</I
></TT
> bytes of <TT
CLASS="PARAMETER"
><I
>buffer</I
></TT
> are available to write to.
</P
><P
> This function returns the number of bytes transferred (if zero
or positive), or else an error code.
</P
></DIV
><DIV
CLASS="NAVFOOTER"
><HR
ALIGN="LEFT"
WIDTH="100%"><TABLE
SUMMARY="Footer navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
><A
HREF="r1739.html"
ACCESSKEY="P"
><<< Previous</A
></TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="book1.html"
ACCESSKEY="H"
>Home</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
><A
HREF="r1833.html"
ACCESSKEY="N"
>Next >>></A
></TD
></TR
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
><SPAN
CLASS="phrase"
><SPAN
CLASS="PHRASE"
>parport_write</SPAN
></SPAN
></TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="a950.html"
ACCESSKEY="U"
>Up</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
><SPAN
CLASS="phrase"
><SPAN
CLASS="PHRASE"
>parport_set_timeout</SPAN
></SPAN
></TD
></TR
></TABLE
></DIV
></BODY
></HTML
>
