<?xml version="1.0" encoding="ANSI_X3.4-1968" standalone="no"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968" /><title>__copy_to_user</title><meta name="generator" content="DocBook XSL Stylesheets V1.76.1" /><link rel="home" href="index.html" title="The Linux Kernel API" /><link rel="up" href="ch04s02.html" title="User Space Memory Access" /><link rel="prev" href="API---copy-to-user-inatomic.html" title="__copy_to_user_inatomic" /><link rel="next" href="API---copy-from-user.html" title="__copy_from_user" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center"><span>__copy_to_user</span></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="API---copy-to-user-inatomic.html">Prev</a> </td><th width="60%" align="center">User Space Memory Access</th><td width="20%" align="right"> <a accesskey="n" href="API---copy-from-user.html">Next</a></td></tr></table><hr /></div><div class="refentry" title="__copy_to_user"><a id="API---copy-to-user"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>__copy_to_user — Copy a block of data into user space, with less checking. </p></div><div class="refsynopsisdiv" title="Synopsis"><h2>Synopsis</h2><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">unsigned long __must_check <strong>fsfunc__copy_to_user </strong>(</code></td><td>void __user * <var class="pdparam">to</var>, </td></tr><tr><td> </td><td>const void * <var class="pdparam">from</var>, </td></tr><tr><td> </td><td>unsigned long <var class="pdparam">n</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div><div class="refsect1" title="Arguments"><a id="id2594829"></a><h2>Arguments</h2><div class="variablelist"><dl><dt><span class="term"><em class="parameter"><code>to</code></em></span></dt><dd><p> Destination address, in user space. </p></dd><dt><span class="term"><em class="parameter"><code>from</code></em></span></dt><dd><p> Source address, in kernel space. </p></dd><dt><span class="term"><em class="parameter"><code>n</code></em></span></dt><dd><p> Number of bytes to copy. </p></dd></dl></div></div><div class="refsect1" title="Context"><a id="id2594890"></a><h2>Context</h2><p> User context only. This function may sleep. </p></div><div class="refsect1" title="Description"><a id="id2594900"></a><h2>Description</h2><p> Copy data from kernel space to user space. Caller must check the specified block with <code class="function">access_ok</code> before calling this function. </p><p> Returns number of bytes that could not be copied. On success, this will be zero. </p></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="API---copy-to-user-inatomic.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="ch04s02.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="API---copy-from-user.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top"><span>__copy_to_user_inatomic</span> </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> <span>__copy_from_user</span></td></tr></table></div></body></html>