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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"><html><head><title>Test To See If The Library Is Threadsafe</title><style type="text/css">body { margin: auto; font-family: "Verdana" "sans-serif"; padding: 8px 1%;}a { color: #45735f }a:visited { color: #734559 }.logo { position:absolute; margin:3px; }.tagline { float:right; text-align:right; font-style:italic; width:240px; margin:12px; margin-top:58px;}.toolbar { font-variant: small-caps; text-align: center; line-height: 1.6em; margin: 0; padding:1px 8px;}.toolbar a { color: white; text-decoration: none; padding: 6px 12px; }.toolbar a:visited { color: white; }.toolbar a:hover { color: #80a796; background: white; }.content { margin: 5%; }.content dt { font-weight:bold; }.content dd { margin-bottom: 25px; margin-left:20%; }.content ul { padding:0px; padding-left: 15px; margin:0px; }/* rounded corners */.se { background: url(../images/se.png) 100% 100% no-repeat #80a796}.sw { background: url(../images/sw.png) 0% 100% no-repeat }.ne { background: url(../images/ne.png) 100% 0% no-repeat }.nw { background: url(../images/nw.png) 0% 0% no-repeat }</style><meta http-equiv="content-type" content="text/html; charset=UTF-8"> </head><body><div><!-- container div to satisfy validator --><a href="../index.html"><img class="logo" src="../images/SQLite.gif" alt="SQLite Logo" border="0"></a><div><!-- IE hack to prevent disappearing logo--></div><div class="tagline">Small. Fast. Reliable.<br>Choose any three.</div><table width=100% style="clear:both"><tr><td> <div class="se"><div class="sw"><div class="ne"><div class="nw"> <div class="toolbar"> <a href="../about.html">About</a> <a href="../sitemap.html">Sitemap</a> <a href="../docs.html">Documentation</a> <a href="../download.html">Download</a> <a href="../copyright.html">License</a> <a href="../news.html">News</a> <a href="http://www.sqlite.org/cvstrac/index">Developers</a> <a href="../support.html">Support</a> </div></div></div></div></div></td></tr></table> <a href="intro.html"><h2>SQLite C Interface</h2></a><h2>Test To See If The Library Is Threadsafe</h2><blockquote><pre>int sqlite3_threadsafe(void);</pre></blockquote><p>SQLite can be compiled with or without mutexes. Whenthe <a href="../compile.html#threadsafe">SQLITE_THREADSAFE</a> C preprocessor macro 1 or 2, mutexesare enabled and SQLite is threadsafe. When the<a href="../compile.html#threadsafe">SQLITE_THREADSAFE</a> macro is 0,the mutexes are omitted. Without the mutexes, it is not safeto use SQLite concurrently from more than one thread.</p><p>Enabling mutexes incurs a measurable performance penalty.So if speed is of utmost importance, it makes sense to disablethe mutexes. But for maximum safety, mutexes should be enabled.The default behavior is for mutexes to be enabled.</p><p>This interface can be used by a program to make sure that theversion of SQLite that it is linking against was compiled withthe desired setting of the <a href="../compile.html#threadsafe">SQLITE_THREADSAFE</a> macro.</p><p>This interface only reports on the compile-time mutex settingof the <a href="../compile.html#threadsafe">SQLITE_THREADSAFE</a> flag. If SQLite is compiled withSQLITE_THREADSAFE=1 then mutexes are enabled by default butcan be fully or partially disabled using a call to <a href="../c3ref/config.html">sqlite3_config()</a>with the verbs <a href="../c3ref/c_config_getmalloc.html">SQLITE_CONFIG_SINGLETHREAD</a>, <a href="../c3ref/c_config_getmalloc.html">SQLITE_CONFIG_MULTITHREAD</a>,or <a href="../c3ref/c_config_getmalloc.html">SQLITE_CONFIG_MUTEX</a>. The return value of this function showsonly the default compile-time setting, not any run-time changesto that setting.</p><p>See the <a href="../threadsafe.html">threading mode</a> documentation for additional information.</p><p><h3>Invariants:</h3><table border="0" cellpadding="5" cellspacing="0"><tr><td valign="top">H10101</td> <td valign="top">The <a href="../c3ref/threadsafe.html">sqlite3_threadsafe()</a> function shall return zero ifand only if SQLite was compiled with mutexing code omitted.</td></tr><tr><td valign="top">H10102</td> <td valign="top">The value returned by the <a href="../c3ref/threadsafe.html">sqlite3_threadsafe()</a> functionshall remain the same across calls to <a href="../c3ref/config.html">sqlite3_config()</a>.</td></tr></table></p><p>See also lists of <a href="objlist.html">Objects</a>, <a href="constlist.html">Constants</a>, and <a href="funclist.html">Functions</a>.</p><hr><small><i>This page last modified 2008/12/09 18:44:04 UTC</i></small></div></body></html>⌨️ 快捷键说明
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