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<a name="Code_002dLevel-And-API-Options"></a>
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<hr>
<a name="Code_002dLevel-And-API-Options-1"></a>
<h3 class="section">16.3 Code-Level And API Options</h3>

<dl compact="compact">
<dd>
<a name="option_002dansi_002ddefinitions"></a><a name="index-_002d_002d_002doption_002dansi_002ddefinitions"></a>
<a name="index-ansi_002ddefinitions"></a>
</dd>
<dt>&lsquo;<samp>--ansi-definitions, <code>%option ansi-definitions</code></samp>&rsquo;</dt>
<dd><p>Deprecated, ignored
</p>
<a name="option_002dansi_002dprototypes"></a><a name="index-_002d_002d_002doption_002dansi_002dprototypes"></a>
<a name="index-ansi_002dprototypes"></a>
</dd>
<dt>&lsquo;<samp>--ansi-prototypes, <code>%option ansi-prototypes</code></samp>&rsquo;</dt>
<dd><p>Deprecated, ignored
</p>
<a name="option_002dbison_002dbridge"></a><a name="index-_002d_002d_002dbison_002dbridge"></a>
<a name="index-bison_002dbridge"></a>
</dd>
<dt>&lsquo;<samp>--bison-bridge, <code>%option bison-bridge</code></samp>&rsquo;</dt>
<dd><p>instructs flex to generate a C scanner that is
meant to be called by a
<code>GNU bison</code>
parser. The scanner has minor API changes for
<code>bison</code>
compatibility. In particular, the declaration of
<code>yylex</code>
is modified to take an additional parameter,
<code>yylval</code>.
See <a href="Bison-Bridge.html#Bison-Bridge">Bison Bridge</a>.
</p>
<a name="option_002dbison_002dlocations"></a><a name="index-_002d_002d_002dbison_002dlocations"></a>
<a name="index-bison_002dlocations"></a>
</dd>
<dt>&lsquo;<samp>--bison-locations, <code>%option bison-locations</code></samp>&rsquo;</dt>
<dd><p>instruct flex that 
<code>GNU bison</code> <code>%locations</code> are being used.
This means <code>yylex</code> will be passed
an additional parameter, <code>yylloc</code>. This option
implies <code>%option bison-bridge</code>.
See <a href="Bison-Bridge.html#Bison-Bridge">Bison Bridge</a>.
</p>
<a name="option_002dnoline"></a><a name="index-_002dL"></a>
<a name="index-_002d_002d_002dnoline"></a>
<a name="index-noline"></a>
</dd>
<dt>&lsquo;<samp>-L, --noline, <code>%option noline</code></samp>&rsquo;</dt>
<dd><p>instructs
<code>flex</code>
not to generate
<code>#line</code>
directives.  Without this option,
<code>flex</code>
peppers the generated scanner
with <code>#line</code> directives so error messages in the actions will be correctly
located with respect to either the original
<code>flex</code>
input file (if the errors are due to code in the input file), or
<samp>lex.yy.c</samp>
(if the errors are
<code>flex</code>&rsquo;s
fault &ndash; you should report these sorts of errors to the email address
given in <a href="Reporting-Bugs.html#Reporting-Bugs">Reporting Bugs</a>).
</p>


<a name="option_002dreentrant"></a><a name="index-_002dR"></a>
<a name="index-_002d_002d_002dreentrant"></a>
<a name="index-reentrant"></a>
</dd>
<dt>&lsquo;<samp>-R, --reentrant, <code>%option reentrant</code></samp>&rsquo;</dt>
<dd><p>instructs flex to generate a reentrant C scanner.  The generated scanner
may safely be used in a multi-threaded environment. The API for a
reentrant scanner is different than for a non-reentrant scanner
see <a href="Reentrant.html#Reentrant">Reentrant</a>).  Because of the API difference between
reentrant and non-reentrant <code>flex</code> scanners, non-reentrant flex
code must be modified before it is suitable for use with this option.
This option is not compatible with the &lsquo;<samp>--c++</samp>&rsquo; option.
</p>
<p>The option &lsquo;<samp>--reentrant</samp>&rsquo; does not affect the performance of
the scanner.
</p>


<a name="option_002dc_002b_002b"></a><a name="index-_002d_002b"></a>
<a name="index-_002d_002d_002dc_002b_002b"></a>
<a name="index-c_002b_002b"></a>
</dd>
<dt>&lsquo;<samp>-+, --c++, <code>%option c++</code></samp>&rsquo;</dt>
<dd><p>specifies that you want flex to generate a C++
scanner class.  See <a href="Cxx.html#Cxx">Cxx</a>, for
details.
</p>


<a name="option_002darray"></a><a name="index-_002d_002d_002darray"></a>
<a name="index-array"></a>
</dd>
<dt>&lsquo;<samp>--array, <code>%option array</code></samp>&rsquo;</dt>
<dd><p>specifies that you want yytext to be an array instead of a char*
</p>


<a name="option_002dpointer"></a><a name="index-_002d_002d_002dpointer"></a>
<a name="index-pointer"></a>
</dd>
<dt>&lsquo;<samp>--pointer, <code>%option pointer</code></samp>&rsquo;</dt>
<dd><p>specify that  <code>yytext</code> should be a <code>char *</code>, not an array.
This default is <code>char *</code>.
</p>


<a name="option_002dprefix"></a><a name="index-_002dP"></a>
<a name="index-_002d_002d_002dprefix"></a>
<a name="index-prefix"></a>
</dd>
<dt>&lsquo;<samp>-PPREFIX, --prefix=PREFIX, <code>%option prefix=&quot;PREFIX&quot;</code></samp>&rsquo;</dt>
<dd><p>changes the default &lsquo;<samp>yy</samp>&rsquo; prefix used by <code>flex</code> for all
globally-visible variable and function names to instead be
&lsquo;<samp>PREFIX</samp>&rsquo;.  For example, &lsquo;<samp>--prefix=foo</samp>&rsquo; changes the name of
<code>yytext</code> to <code>footext</code>.  It also changes the name of the default
output file from <samp>lex.yy.c</samp> to <samp>lex.foo.c</samp>.  Here is a partial
list of the names affected:
</p>
<div class="example">
<pre class="verbatim">    yy_create_buffer
    yy_delete_buffer
    yy_flex_debug
    yy_init_buffer
    yy_flush_buffer
    yy_load_buffer_state
    yy_switch_to_buffer
    yyin
    yyleng
    yylex
    yylineno
    yyout
    yyrestart
    yytext
    yywrap
    yyalloc
    yyrealloc
    yyfree
</pre></div>

<p>(If you are using a C++ scanner, then only <code>yywrap</code> and
<code>yyFlexLexer</code> are affected.)  Within your scanner itself, you can
still refer to the global variables and functions using either version
of their name; but externally, they have the modified name.
</p>
<p>This option lets you easily link together multiple
<code>flex</code>
programs into the same executable.  Note, though, that using this
option also renames
<code>yywrap()</code>,
so you now
<em>must</em>
either
provide your own (appropriately-named) version of the routine for your
scanner, or use
<code>%option noyywrap</code>,
as linking with
&lsquo;<samp>-lfl</samp>&rsquo;
no longer provides one for you by default.
</p>


<a name="option_002dmain"></a><a name="index-_002d_002d_002dmain"></a>
<a name="index-main"></a>
</dd>
<dt>&lsquo;<samp>--main, <code>%option main</code></samp>&rsquo;</dt>
<dd><p>directs flex to provide a default <code>main()</code> program for the
scanner, which simply calls <code>yylex()</code>.  This option implies
<code>noyywrap</code> (see below).
</p>


<a name="option_002dnounistd"></a><a name="index-_002d_002d_002dnounistd"></a>
<a name="index-nounistd"></a>
</dd>
<dt>&lsquo;<samp>--nounistd, <code>%option nounistd</code></samp>&rsquo;</dt>
<dd><p>suppresses inclusion of the non-ANSI header file <samp>unistd.h</samp>. This option
is meant to target environments in which <samp>unistd.h</samp> does not exist. Be aware
that certain options may cause flex to generate code that relies on functions
normally found in <samp>unistd.h</samp>, (e.g. <code>isatty()</code>, <code>read()</code>.)
If you wish to use these functions, you will have to inform your compiler where
to find them.
See <a href="Options-Affecting-Scanner-Behavior.html#option_002dalways_002dinteractive">option-always-interactive</a>. See <a href="Options-for-Scanner-Speed-and-Size.html#option_002dread">option-read</a>.
</p>


<a name="option_002dyyclass"></a><a name="index-_002d_002d_002dyyclass"></a>
<a name="index-yyclass"></a>
</dd>
<dt>&lsquo;<samp>--yyclass=NAME, <code>%option yyclass=&quot;NAME&quot;</code></samp>&rsquo;</dt>
<dd><p>only applies when generating a C++ scanner (the &lsquo;<samp>--c++</samp>&rsquo; option).  It
informs <code>flex</code> that you have derived <code>NAME</code> as a subclass of
<code>yyFlexLexer</code>, so <code>flex</code> will place your actions in the member
function <code>foo::yylex()</code> instead of <code>yyFlexLexer::yylex()</code>.  It
also generates a <code>yyFlexLexer::yylex()</code> member function that emits
a run-time error (by invoking <code>yyFlexLexer::LexerError())</code> if
called.  See <a href="Cxx.html#Cxx">Cxx</a>.
</p>
</dd>
</dl>

<hr>
<div class="header">
<p>
Next: <a href="Options-for-Scanner-Speed-and-Size.html#Options-for-Scanner-Speed-and-Size" accesskey="n" rel="next">Options for Scanner Speed and Size</a>, Previous: <a href="Options-Affecting-Scanner-Behavior.html#Options-Affecting-Scanner-Behavior" accesskey="p" rel="prev">Options Affecting Scanner Behavior</a>, Up: <a href="Scanner-Options.html#Scanner-Options" accesskey="u" rel="up">Scanner Options</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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