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Next: <a href="Tables-File-Format.html#Tables-File-Format" accesskey="n" rel="next">Tables File Format</a>, Previous: <a href="Creating-Serialized-Tables.html#Creating-Serialized-Tables" accesskey="p" rel="prev">Creating Serialized Tables</a>, Up: <a href="Serialized-Tables.html#Serialized-Tables" accesskey="u" rel="up">Serialized Tables</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Indices.html#Indices" title="Index" rel="index">Index</a>]</p>
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<a name="Loading-and-Unloading-Serialized-Tables-1"></a>
<h3 class="section">22.2 Loading and Unloading Serialized Tables</h3>
<a name="index-tables_002c-loading-and-unloading"></a>
<a name="index-loading-tables-at-runtime"></a>
<a name="index-tables_002c-freeing"></a>
<a name="index-freeing-tables"></a>
<a name="index-memory_002c-serialized-tables-1"></a>

<p>If you&rsquo;ve built your scanner with <code>%option tables-file</code>, then you must
load the scanner tables at runtime. This can be accomplished with the following
function:
</p>
<dl>
<dt><a name="index-yytables_005ffload"></a>Function: <em>int</em> <strong>yytables_fload</strong> <em>(FILE* <var>fp</var> [, yyscan_t <var>scanner</var>])</em></dt>
<dd><p>Locates scanner tables in the stream pointed to by <var>fp</var> and loads them.
Memory for the tables is allocated via <code>yyalloc</code>.  You must call this
function before the first call to <code>yylex</code>. The argument <var>scanner</var>
only appears in the reentrant scanner.
This function returns &lsquo;<samp>0</samp>&rsquo; (zero) on success, or non-zero on error.
</p></dd></dl>

<p>The loaded tables are <strong>not</strong> automatically destroyed (unloaded) when you
call <code>yylex_destroy</code>. The reason is that you may create several scanners
of the same type (in a reentrant scanner), each of which needs access to these
tables.  To avoid a nasty memory leak, you must call the following function:
</p>
<dl>
<dt><a name="index-yytables_005fdestroy"></a>Function: <em>int</em> <strong>yytables_destroy</strong> <em>([yyscan_t <var>scanner</var>])</em></dt>
<dd><p>Unloads the scanner tables. The tables must be loaded again before you can scan
any more data.  The argument <var>scanner</var> only appears in the reentrant
scanner.  This function returns &lsquo;<samp>0</samp>&rsquo; (zero) on success, or non-zero on
error.
</p></dd></dl>

<p><strong>The functions <code>yytables_fload</code> and <code>yytables_destroy</code> are not
thread-safe.</strong> You must ensure that these functions are called exactly once (for
each scanner type) in a threaded program, before any thread calls <code>yylex</code>.
After the tables are loaded, they are never written to, and no thread
protection is required thereafter &ndash; until you destroy them.
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flex-doc 2.6.4-6 / usr / share / doc / flex-doc / html / Loading-and-Unloading-Serialized-Tables.html
