<?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>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><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> </td><th width="60%" align="center">Kernel utility functions</th><td width="20%" align="right"> <a accesskey="n" href="API-min-not-zero.html">Next</a></td></tr></table><hr /></div><div class="refentry"><a id="API-trace-puts"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>trace_puts — write a string into the ftrace buffer </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"> <strong class="fsfunc">trace_puts </strong>(</code></td><td> <var class="pdparam">str</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div><div class="refsect1"><a id="idm140404966243472"></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> the string to record </p></dd></dl></div></div><div class="refsect1"><a id="idm140404966240304"></a><h2>Note</h2><p> __trace_bputs is an internal function for trace_puts and the <em class="parameter"><code>ip</code></em> is passed in via the trace_puts macro. </p><p> This is similar to <code class="function">trace_printk</code> but is made for those really fast paths that a developer wants the least amount of <span class="quote">“<span class="quote">Heisenbug</span>”</span> affects, where the processing of the print format is still too much. </p><p> This function allows a kernel developer to debug fast path sections that printk is not appropriate for. By scattering in various printk like tracing in the code, a developer can quickly see where problems are occurring. </p><p> This is intended as a debugging tool for the developer only. Please refrain from leaving trace_puts scattered around in your code. (Extra memory is used for special buffers that are allocated when <code class="function">trace_puts</code> is used) </p></div><div class="refsect1"><a id="idm140404966235008"></a><h2>Returns</h2><p> 0 if nothing was written, positive # if string was. (1 when __trace_bputs is used, strlen(str) when __trace_puts is used) </p></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="API-trace-printk.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="ch01s09.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="API-min-not-zero.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top"><span class="phrase">trace_printk</span> </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> <span class="phrase">min_not_zero</span></td></tr></table></div></body></html>