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<h1 class="title">chronos/sendfile</h1>
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<a class="reference reference-toplevel" href="#12" id="62">Procs</a>
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<li><a class="reference" href="#sendfile%2Cint%2Cint%2Cint%2Cint"
title="sendfile(outfd, infd: int; offset: int; count: var int): int">sendfile(outfd, infd: int; offset: int; count: var int): int</a></li>
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&nbsp;&nbsp;<a
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<p class="module-desc">This module provides cross-platform wrapper for <tt class="docutils literal"><span class="pre">sendfile()</span></tt> syscall.</p>
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<h1><a class="toc-backref" href="#12">Procs</a></h1>
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<div id="sendfile,int,int,int,int">
<dt><pre><span class="Keyword">proc</span> <a href="#sendfile%2Cint%2Cint%2Cint%2Cint"><span class="Identifier">sendfile</span></a><span class="Other">(</span><span class="Identifier">outfd</span><span class="Other">,</span> <span class="Identifier">infd</span><span class="Other">:</span> <span class="Identifier">int</span><span class="Other">;</span> <span class="Identifier">offset</span><span class="Other">:</span> <span class="Identifier">int</span><span class="Other">;</span> <span class="Identifier">count</span><span class="Other">:</span> <span class="Keyword">var</span> <span class="Identifier">int</span><span class="Other">)</span><span class="Other">:</span> <span class="Identifier">int</span> {.<span><span class="Other pragmadots">...</span></span><span class="pragmawrap"><span class="Identifier">raises</span><span class="Other">:</span> <span class="Other">[</span><span class="Other">]</span><span class="Other">,</span>
<span class="Identifier">tags</span><span class="Other">:</span> <span class="Other">[</span><span class="Other">]</span></span>.}</pre></dt>
<dd>
<p>Copies data between file descriptor <tt class="docutils literal"><span class="pre">infd</span></tt> and <tt class="docutils literal"><span class="pre">outfd</span></tt>. Because this copying is done within the kernel, <tt class="docutils literal"><span class="pre">sendfile()</span></tt> is more efficient than the combination of <tt class="docutils literal"><span class="pre">read(2)</span></tt> and <tt class="docutils literal"><span class="pre">write(2)</span></tt>, which would require transferring data to and from user space.</p>
<p><tt class="docutils literal"><span class="pre">infd</span></tt> should be a file descriptor opened for reading and <tt class="docutils literal"><span class="pre">outfd</span></tt> should be a descriptor opened for writing.</p>
<p>The <tt class="docutils literal"><span class="pre">infd</span></tt> argument must correspond to a file which supports <tt class="docutils literal"><span class="pre">mmap(2)</span></tt>-like operations (i.e., it cannot be a socket).</p>
<p><tt class="docutils literal"><span class="pre">offset</span></tt> the file offset from which <tt class="docutils literal"><span class="pre">sendfile()</span></tt> will start reading data from <tt class="docutils literal"><span class="pre">infd</span></tt>.</p>
<p><tt class="docutils literal"><span class="pre">count</span></tt> is the number of bytes to copy between the file descriptors. On exit <tt class="docutils literal"><span class="pre">count</span></tt> will hold number of bytes actually transferred between file descriptors. May be &gt;0 even in the case of error return, if some bytes were sent before the error occurred.</p>
<p>If the transfer was successful, the number of bytes written to <tt class="docutils literal"><span class="pre">outfd</span></tt> is stored in <tt class="docutils literal"><span class="pre">count</span></tt>, and <tt class="docutils literal"><span class="pre">0</span></tt> returned. Note that a successful call to <tt class="docutils literal"><span class="pre">sendfile()</span></tt> may write fewer bytes than requested; the caller should be prepared to retry the call if there were unsent bytes.</p>
<p>On error, <tt class="docutils literal"><span class="pre">-1</span></tt> is returned.</p>
&nbsp;&nbsp;<a
href="https://github.com/status-im/nim-chronos/tree/master/chronos/sendfile.nim#L15"
class="link-seesrc" target="_blank">Source</a>
&nbsp;&nbsp;<a href="https://github.com/status-im/nim-chronos/edit/devel/chronos/sendfile.nim#L15" class="link-seesrc" target="_blank" >Edit</a>
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<small style="color: var(--hint);">Made with Nim. Generated: 2024-11-28 08:22:46 UTC</small>
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