<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN""http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >comedi_do_insn</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK REL="HOME" TITLE=" Comedi " HREF="index.html"><LINK REL="UP" TITLE=" Comedi Function Reference " HREF="x4629.html#FUNCTIONREFERENCE"><LINK REL="PREVIOUS" TITLE="comedi_do_insnlist" HREF="r5527.html"><LINK REL="NEXT" TITLE="comedi_lock" HREF="r5574.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" >Comedi: The <SPAN CLASS="emphasis" ><I CLASS="EMPHASIS" >Control and Measurement Device Interface</I ></SPAN > handbook </TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="r5527.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="r5574.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="FUNC-REF-COMEDI-DO-INSN" ></A >comedi_do_insn</H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN5557" ></A ><H2 >Name</H2 >comedi_do_insn -- perform instruction</DIV ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN5560" ></A ><H2 >Synopsis</H2 ><DIV CLASS="FUNCSYNOPSIS" ><P ></P ><A NAME="AEN5561" ></A ><PRE CLASS="FUNCSYNOPSISINFO" >#include <comedilib.h></PRE ><P ><CODE ><CODE CLASS="FUNCDEF" >int comedi_do_insn</CODE >(comedi_t * device, comedi_insn * instruction);</CODE ></P ><P ></P ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN5570" ></A ><H2 > Description </H2 ><P >The function comedi_do_insn() performs a single instruction. If sucessful, comedi_do_insn() returns the number of samples measured, which may be less than the number of requested samples. Comedi limits the number of requested samples in order to enforce fairness among processes. If there is an error, -1 is returned.</P ><P > </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="r5527.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="r5574.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >comedi_do_insnlist</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="x4629.html#FUNCTIONREFERENCE" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >comedi_lock</TD ></TR ></TABLE ></DIV ></BODY ></HTML >