1<html><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968"><title>trace_puts</title><meta name="generator" content="DocBook XSL Stylesheets V1.78.1"><link rel="home" href="index.html" title="Linux Device Drivers"><link rel="up" href="ch01s09.html" title="Kernel utility functions"><link rel="prev" href="API-trace-printk.html" title="trace_printk"><link rel="next" href="API-min-not-zero.html" title="min_not_zero"></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">trace_puts</span></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="API-trace-printk.html">Prev</a>&#160;</td><th width="60%" align="center">Kernel utility functions</th><td width="20%" align="right">&#160;<a accesskey="n" href="API-min-not-zero.html">Next</a></td></tr></table><hr></div><div class="refentry"><a name="API-trace-puts"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>trace_puts &#8212; 
2     write a string into the ftrace buffer
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"> <b class="fsfunc">trace_puts </b>(</code></td><td> <var class="pdparam">str</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer">&#160;</div></div></div><div class="refsect1"><a name="idp1108364348"></a><h2>Arguments</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term"><em class="parameter"><code>str</code></em></span></dt><dd><p>
4     the string to record
5    </p></dd></dl></div></div><div class="refsect1"><a name="idp1108365948"></a><h2>Note</h2><p>
6   __trace_bputs is an internal function for trace_puts and
7   the <em class="parameter"><code>ip</code></em> is passed in via the trace_puts macro.
8   </p><p>
9
10   This is similar to <code class="function">trace_printk</code> but is made for those really fast
11   paths that a developer wants the least amount of <span class="quote">&#8220;<span class="quote">Heisenbug</span>&#8221;</span> affects,
12   where the processing of the print format is still too much.
13   </p><p>
14
15   This function allows a kernel developer to debug fast path sections
16   that printk is not appropriate for. By scattering in various
17   printk like tracing in the code, a developer can quickly see
18   where problems are occurring.
19   </p><p>
20
21   This is intended as a debugging tool for the developer only.
22   Please refrain from leaving trace_puts scattered around in
23   your code. (Extra memory is used for special buffers that are
24   allocated when <code class="function">trace_puts</code> is used)
25</p></div><div class="refsect1"><a name="idp1108368980"></a><h2>Returns</h2><p>
26   0 if nothing was written, positive # if string was.
27   (1 when __trace_bputs is used, strlen(str) when __trace_puts is used)
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