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<html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968" /><title>struct usb_interface_cache</title><meta name="generator" content="DocBook XSL Stylesheets V1.75.2" /><link rel="home" href="index.html" title="The Linux-USB Host Side API" /><link rel="up" href="ch04.html" title="Chapter 4. Host-Side Data Types and Macros" /><link rel="prev" href="re18.html" title="struct usb_interface" /><link rel="next" href="re20.html" title="struct usb_host_config" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center"><span>struct usb_interface_cache</span></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="re18.html">Prev</a> </td><th width="60%" align="center">Chapter 4. Host-Side Data Types and Macros</th><td width="20%" align="right"> <a accesskey="n" href="re20.html">Next</a></td></tr></table><hr /></div><div class="refentry" title="struct usb_interface_cache"><a id="API-struct-usb-interface-cache"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>struct usb_interface_cache —
long-term representation of a device interface
</p></div><div class="refsynopsisdiv" title="Synopsis"><h2>Synopsis</h2><pre class="programlisting">
struct usb_interface_cache {
unsigned num_altsetting;
struct kref ref;
struct usb_host_interface altsetting[0];
}; </pre></div><div class="refsect1" title="Members"><a id="id2738276"></a><h2>Members</h2><div class="variablelist"><dl><dt><span class="term">num_altsetting</span></dt><dd><p>
number of altsettings defined.
</p></dd><dt><span class="term">ref</span></dt><dd><p>
reference counter.
</p></dd><dt><span class="term">altsetting[0]</span></dt><dd><p>
variable-length array of interface structures, one for
each alternate setting that may be selected. Each one includes a
set of endpoint configurations. They will be in no particular order.
</p></dd></dl></div></div><div class="refsect1" title="Description"><a id="id2738322"></a><h2>Description</h2><p>
These structures persist for the lifetime of a usb_device, unlike
struct usb_interface (which persists only as long as its configuration
is installed). The altsetting arrays can be accessed through these
structures at any time, permitting comparison of configurations and
providing support for the /proc/bus/usb/devices pseudo-file.
</p></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="re18.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="ch04.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="re20.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top"><span>struct usb_interface</span> </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> <span>struct usb_host_config</span></td></tr></table></div></body></html>
