139 lines
5.4 KiB
HTML
139 lines
5.4 KiB
HTML
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<title>Test To See If The Library Is Threadsafe</title>
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<!-- keywords: sqlite3_threadsafe -->
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<a href="intro.html"><h2>SQLite C Interface</h2></a>
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<h2>Test To See If The Library Is Threadsafe</h2>
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</div>
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<blockquote><pre>
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int sqlite3_threadsafe(void);
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</pre></blockquote>
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<p>
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The sqlite3_threadsafe() function returns zero if and only if
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SQLite was compiled with mutexing code omitted due to the
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<a href="../compile.html#threadsafe">SQLITE_THREADSAFE</a> compile-time option being set to 0.</p>
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<p>SQLite can be compiled with or without mutexes. When
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the <a href="../compile.html#threadsafe">SQLITE_THREADSAFE</a> C preprocessor macro is 1 or 2, mutexes
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are enabled and SQLite is threadsafe. When the
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<a href="../compile.html#threadsafe">SQLITE_THREADSAFE</a> macro is 0,
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the mutexes are omitted. Without the mutexes, it is not safe
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to use SQLite concurrently from more than one thread.</p>
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<p>Enabling mutexes incurs a measurable performance penalty.
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So if speed is of utmost importance, it makes sense to disable
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the mutexes. But for maximum safety, mutexes should be enabled.
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The default behavior is for mutexes to be enabled.</p>
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<p>This interface can be used by an application to make sure that the
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version of SQLite that it is linking against was compiled with
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the desired setting of the <a href="../compile.html#threadsafe">SQLITE_THREADSAFE</a> macro.</p>
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<p>This interface only reports on the compile-time mutex setting
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of the <a href="../compile.html#threadsafe">SQLITE_THREADSAFE</a> flag. If SQLite is compiled with
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SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but
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can be fully or partially disabled using a call to <a href="../c3ref/config.html">sqlite3_config()</a>
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with the verbs <a href="../c3ref/c_config_covering_index_scan.html#sqliteconfigsinglethread">SQLITE_CONFIG_SINGLETHREAD</a>, <a href="../c3ref/c_config_covering_index_scan.html#sqliteconfigmultithread">SQLITE_CONFIG_MULTITHREAD</a>,
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or <a href="../c3ref/c_config_covering_index_scan.html#sqliteconfigserialized">SQLITE_CONFIG_SERIALIZED</a>. The return value of the
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sqlite3_threadsafe() function shows only the compile-time setting of
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thread safety, not any run-time changes to that setting made by
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sqlite3_config(). In other words, the return value from sqlite3_threadsafe()
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is unchanged by calls to sqlite3_config().</p>
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<p>See the <a href="../threadsafe.html">threading mode</a> documentation for additional information.
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</p><p>See also lists of
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<a href="objlist.html">Objects</a>,
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<a href="constlist.html">Constants</a>, and
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<a href="funclist.html">Functions</a>.</p>
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