<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"> <HTML ><HEAD ><TITLE >parport_write</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_negotiate" HREF="r1703.html"><LINK REL="NEXT" TITLE="parport_read" HREF="r1786.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="r1703.html" ACCESSKEY="P" ><<< Previous</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="r1786.html" ACCESSKEY="N" >Next >>></A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="AEN1739" ></A ><SPAN CLASS="phrase" ><SPAN CLASS="PHRASE" >parport_write</SPAN ></SPAN ></H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN1743" ></A ><H2 >Name</H2 >parport_write -- write a block of data to a parallel port </DIV ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN1746" ></A ><H2 >Synopsis</H2 ><DIV CLASS="FUNCSYNOPSIS" ><A NAME="AEN1748" ></A ><P ></P ><P ><CODE ><CODE CLASS="FUNCDEF" >ssize_t <TT CLASS="FUNCTION" >parport_write </TT ></CODE >(struct parport * <TT CLASS="PARAMETER" ><I >port</I ></TT >, const 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="AEN1758" ></A ><H2 >Arguments</H2 ><P ></P ><DIV CLASS="VARIABLELIST" ><DL ><DT ><TT CLASS="PARAMETER" ><I >port</I ></TT ></DT ><DD ><P > port to write to </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="AEN1776" ></A ><H2 >Description</H2 ><P > This will write 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 forward transfers (host to peripheral). </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 valid. </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="r1703.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="r1786.html" ACCESSKEY="N" >Next >>></A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><SPAN CLASS="phrase" ><SPAN CLASS="PHRASE" >parport_negotiate</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_read</SPAN ></SPAN ></TD ></TR ></TABLE ></DIV ></BODY ></HTML >