1<html><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968"><title>usb_get_current_frame_number</title><meta name="generator" content="DocBook XSL Stylesheets V1.78.1"><link rel="home" href="index.html" title="The Linux-USB Host Side API"><link rel="up" href="usbcore.html" title="Chapter&#160;5.&#160;USB Core APIs"><link rel="prev" href="API-usb-lock-device-for-reset.html" title="usb_lock_device_for_reset"><link rel="next" href="API-usb-alloc-coherent.html" title="usb_alloc_coherent"></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_get_current_frame_number</span></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="API-usb-lock-device-for-reset.html">Prev</a>&#160;</td><th width="60%" align="center">Chapter&#160;5.&#160;USB Core APIs</th><td width="20%" align="right">&#160;<a accesskey="n" href="API-usb-alloc-coherent.html">Next</a></td></tr></table><hr></div><div class="refentry"><a name="API-usb-get-current-frame-number"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>usb_get_current_frame_number &#8212; 
2     return current bus frame number
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_get_current_frame_number </b>(</code></td><td>struct usb_device * <var class="pdparam">dev</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer">&#160;</div></div></div><div class="refsect1"><a name="idp1116556068"></a><h2>Arguments</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term"><em class="parameter"><code>dev</code></em></span></dt><dd><p>
4     the device whose bus is being queried
5    </p></dd></dl></div></div><div class="refsect1"><a name="idp1116557684"></a><h2>Return</h2><p>
6   The current frame number for the USB host controller used
7   with the given USB device. This can be used when scheduling
8   isochronous requests.
9</p></div><div class="refsect1"><a name="idp1116558436"></a><h2>Note</h2><p>
10   Different kinds of host controller have different <span class="quote">&#8220;<span class="quote">scheduling
11   horizons</span>&#8221;</span>. While one type might support scheduling only 32 frames
12   into the future, others could support scheduling up to 1024 frames
13   into the future.
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