1<html><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968"><title>usb_ep_fifo_status</title><meta name="generator" content="DocBook XSL Stylesheets V1.78.1"><link rel="home" href="index.html" title="USB Gadget API for Linux"><link rel="up" href="core.html" title="Core Objects and Methods"><link rel="prev" href="API-usb-ep-set-wedge.html" title="usb_ep_set_wedge"><link rel="next" href="API-usb-ep-fifo-flush.html" title="usb_ep_fifo_flush"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center"><span class="phrase">usb_ep_fifo_status</span></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="API-usb-ep-set-wedge.html">Prev</a>&#160;</td><th width="60%" align="center">Core Objects and Methods</th><td width="20%" align="right">&#160;<a accesskey="n" href="API-usb-ep-fifo-flush.html">Next</a></td></tr></table><hr></div><div class="refentry"><a name="API-usb-ep-fifo-status"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>usb_ep_fifo_status &#8212; 
2     returns number of bytes in fifo, or error
3 </p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><div class="funcsynopsis"><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">usb_ep_fifo_status </b>(</code></td><td>struct usb_ep * <var class="pdparam">ep</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer">&#160;</div></div></div><div class="refsect1"><a name="idp1124054484"></a><h2>Arguments</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term"><em class="parameter"><code>ep</code></em></span></dt><dd><p>
4     the endpoint whose fifo status is being checked.
5    </p></dd></dl></div></div><div class="refsect1"><a name="idp1124056076"></a><h2>Description</h2><p>
6   FIFO endpoints may have <span class="quote">&#8220;<span class="quote">unclaimed data</span>&#8221;</span> in them in certain cases,
7   such as after aborted transfers.  Hosts may not have collected all
8   the IN data written by the gadget driver (and reported by a request
9   completion).  The gadget driver may not have collected all the data
10   written OUT to it by the host.  Drivers that need precise handling for
11   fault reporting or recovery may need to use this call.
12   </p><p>
13
14   This returns the number of such bytes in the fifo, or a negative
15   errno if the endpoint doesn't use a FIFO or doesn't support such
16   precise handling.
17</p></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="API-usb-ep-set-wedge.html">Prev</a>&#160;</td><td width="20%" align="center"><a accesskey="u" href="core.html">Up</a></td><td width="40%" align="right">&#160;<a accesskey="n" href="API-usb-ep-fifo-flush.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top"><span class="phrase">usb_ep_set_wedge</span>&#160;</td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top">&#160;<span class="phrase">usb_ep_fifo_flush</span></td></tr></table></div></body></html>
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