doc/guide/localhost/CallingFromCToSML

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  22 <a href="./Home">MLton 20180207</a>
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  25 <div id="header">
  26 <h1>CallingFromCToSML</h1>
  27 </div>
  28 <div id="content">
  29 <div id="preamble">
  30 <div class="sectionbody">
  31 <div class="paragraph"><p>MLton&#8217;s <a href="ForeignFunctionInterface">ForeignFunctionInterface</a> allows programs to <em>export</em> SML
  32 functions to be called from C.  Suppose you would like export from SML
  33 a function of type <span class="monospaced">real * char -&gt; int</span> as the C function <span class="monospaced">foo</span>.
  34 MLton extends the syntax of SML to allow expressions like the
  35 following:</p></div>
  36 <div class="listingblock">
  37 <div class="content monospaced">
  38 <pre>_export "foo": (real * char -&gt; int) -&gt; unit;</pre>
  39 </div></div>
  40 <div class="paragraph"><p>The above expression exports a C function named <span class="monospaced">foo</span>, with
  41 prototype</p></div>
  42 <div class="listingblock">
  43 <div class="content"><div class="highlight"><pre><span class="n">Int32</span> <span class="nf">foo</span> <span class="p">(</span><span class="n">Real64</span> <span class="n">x0</span><span class="p">,</span> <span class="n">Char</span> <span class="n">x1</span><span class="p">);</span>
  44 </pre></div></div></div>
  45 <div class="paragraph"><p>The <span class="monospaced">_export</span> expression denotes a function of type
  46 <span class="monospaced">(real * char -&gt; int) -&gt; unit</span> that when called with a function
  47 <span class="monospaced">f</span>, arranges for the exported <span class="monospaced">foo</span> function to call <span class="monospaced">f</span>
  48 when <span class="monospaced">foo</span> is called.  So, for example, the following exports and
  49 defines <span class="monospaced">foo</span>.</p></div>
  50 <div class="listingblock">
  51 <div class="content"><div class="highlight"><pre><span class="k">val</span><span class="w"> </span><span class="n">e</span><span class="w"> </span><span class="p">=</span><span class="w"> </span><span class="p">_</span><span class="n">export</span><span class="w"> </span><span class="s">&quot;foo&quot;</span><span class="p">:</span><span class="w"> </span><span class="p">(</span><span class="n">real</span><span class="w"> </span><span class="n">*</span><span class="w"> </span><span class="n">char</span><span class="w"> </span><span class="p">-&gt;</span><span class="w"> </span><span class="n">int</span><span class="p">)</span><span class="w"> </span><span class="p">-&gt;</span><span class="w"> </span><span class="n">unit</span><span class="p">;</span><span class="w"></span>
  52 <span class="k">val</span><span class="w"> </span><span class="p">_</span><span class="w"> </span><span class="p">=</span><span class="w"> </span><span class="n">e</span><span class="w"> </span><span class="p">(</span><span class="k">fn</span><span class="w"> </span><span class="p">(</span><span class="n">x</span><span class="p">,</span><span class="w"> </span><span class="n">c</span><span class="p">)</span><span class="w"> </span><span class="p">=&gt;</span><span class="w"> </span><span class="mi">13</span><span class="w"> </span><span class="n">+</span><span class="w"> </span><span class="n">Real</span><span class="p">.</span><span class="n">floor</span><span class="w"> </span><span class="n">x</span><span class="w"> </span><span class="n">+</span><span class="w"> </span><span class="n">Char</span><span class="p">.</span><span class="n">ord</span><span class="w"> </span><span class="n">c</span><span class="p">)</span><span class="w"></span>
  53 </pre></div></div></div>
  54 <div class="paragraph"><p>The general form of an <span class="monospaced">_export</span> expression is</p></div>
  55 <div class="listingblock">
  56 <div class="content monospaced">
  57 <pre>_export "C function name" attr... : cFuncTy -&gt; unit;</pre>
  58 </div></div>
  59 <div class="paragraph"><p>The type and the semicolon are not optional.  As with <span class="monospaced">_import</span>, a
  60 sequence of attributes may follow the function name.</p></div>
  61 <div class="paragraph"><p>MLton&#8217;s <span class="monospaced">-export-header</span> option generates a C header file with
  62 prototypes for all of the functions exported from SML.  Include this
  63 header file in your C files to type check calls to functions exported
  64 from SML.  This header file includes <span class="monospaced">typedef</span>s for the
  65 <a href="ForeignFunctionInterfaceTypes"> types that can be passed between SML and C</a>.</p></div>
  66 </div>
  67 </div>
  68 <div class="sect1">
  69 <h2 id="_example">Example</h2>
  70 <div class="sectionbody">
  71 <div class="paragraph"><p>Suppose that <span class="monospaced">export.sml</span> is</p></div>
  72 <div class="listingblock">
  73 <div class="content"><div class="highlight"><pre><span class="k">val</span><span class="w"> </span><span class="n">e</span><span class="w"> </span><span class="p">=</span><span class="w"> </span><span class="p">_</span><span class="n">export</span><span class="w"> </span><span class="s">&quot;f&quot;</span><span class="p">:</span><span class="w"> </span><span class="p">(</span><span class="n">int</span><span class="w"> </span><span class="n">*</span><span class="w"> </span><span class="n">real</span><span class="w"> </span><span class="n">*</span><span class="w"> </span><span class="n">char</span><span class="w"> </span><span class="p">-&gt;</span><span class="w"> </span><span class="n">char</span><span class="p">)</span><span class="w"> </span><span class="p">-&gt;</span><span class="w"> </span><span class="n">unit</span><span class="p">;</span><span class="w"></span>
  74 <span class="k">val</span><span class="w"> </span><span class="p">_</span><span class="w"> </span><span class="p">=</span><span class="w"> </span><span class="n">e</span><span class="w"> </span><span class="p">(</span><span class="k">fn</span><span class="w"> </span><span class="p">(</span><span class="n">i</span><span class="p">,</span><span class="w"> </span><span class="n">r</span><span class="p">,</span><span class="w"> </span><span class="p">_)</span><span class="w"> </span><span class="p">=&gt;</span><span class="w"></span>
  75 <span class="w">           </span><span class="p">(</span><span class="n">print</span><span class="w"> </span><span class="p">(</span><span class="n">concat</span><span class="w"> </span><span class="p">[</span><span class="s">&quot;i = &quot;</span><span class="p">,</span><span class="w"> </span><span class="n">Int</span><span class="p">.</span><span class="n">toString</span><span class="w"> </span><span class="n">i</span><span class="p">,</span><span class="w"></span>
  76 <span class="w">                           </span><span class="s">&quot;  r = &quot;</span><span class="p">,</span><span class="w"> </span><span class="n">Real</span><span class="p">.</span><span class="n">toString</span><span class="w"> </span><span class="n">r</span><span class="p">,</span><span class="w"> </span><span class="s">&quot;</span><span class="se">\n</span><span class="s">&quot;</span><span class="p">])</span><span class="w"></span>
  77 <span class="w">            </span><span class="p">;</span><span class="w"> </span><span class="p">#</span><span class="s">&quot;g&quot;</span><span class="p">))</span><span class="w"></span>
  78 <span class="k">val</span><span class="w"> </span><span class="n">g</span><span class="w"> </span><span class="p">=</span><span class="w"> </span><span class="p">_</span><span class="n">import</span><span class="w"> </span><span class="s">&quot;g&quot;</span><span class="w"> </span><span class="n">public</span><span class="w"> </span><span class="n">reentrant</span><span class="p">:</span><span class="w"> </span><span class="n">unit</span><span class="w"> </span><span class="p">-&gt;</span><span class="w"> </span><span class="n">unit</span><span class="p">;</span><span class="w"></span>
  79 <span class="k">val</span><span class="w"> </span><span class="p">_</span><span class="w"> </span><span class="p">=</span><span class="w"> </span><span class="n">g</span><span class="w"> </span><span class="p">()</span><span class="w"></span>
  80 <span class="k">val</span><span class="w"> </span><span class="p">_</span><span class="w"> </span><span class="p">=</span><span class="w"> </span><span class="n">g</span><span class="w"> </span><span class="p">()</span><span class="w"></span>
  81
  82 <span class="k">val</span><span class="w"> </span><span class="n">e</span><span class="w"> </span><span class="p">=</span><span class="w"> </span><span class="p">_</span><span class="n">export</span><span class="w"> </span><span class="s">&quot;f2&quot;</span><span class="p">:</span><span class="w"> </span><span class="p">(</span><span class="n">Word8</span><span class="p">.</span><span class="n">word</span><span class="w"> </span><span class="p">-&gt;</span><span class="w"> </span><span class="n">word</span><span class="w"> </span><span class="n">array</span><span class="p">)</span><span class="w"> </span><span class="p">-&gt;</span><span class="w"> </span><span class="n">unit</span><span class="p">;</span><span class="w"></span>
  83 <span class="k">val</span><span class="w"> </span><span class="p">_</span><span class="w"> </span><span class="p">=</span><span class="w"> </span><span class="n">e</span><span class="w"> </span><span class="p">(</span><span class="k">fn</span><span class="w"> </span><span class="n">w</span><span class="w"> </span><span class="p">=&gt;</span><span class="w"></span>
  84 <span class="w">           </span><span class="n">Array</span><span class="p">.</span><span class="n">tabulate</span><span class="w"> </span><span class="p">(</span><span class="mi">10</span><span class="p">,</span><span class="w"> </span><span class="k">fn</span><span class="w"> </span><span class="p">_</span><span class="w"> </span><span class="p">=&gt;</span><span class="w"> </span><span class="n">Word</span><span class="p">.</span><span class="n">fromLargeWord</span><span class="w"> </span><span class="p">(</span><span class="n">Word8</span><span class="p">.</span><span class="n">toLargeWord</span><span class="w"> </span><span class="n">w</span><span class="p">)))</span><span class="w"></span>
  85 <span class="k">val</span><span class="w"> </span><span class="n">g2</span><span class="w"> </span><span class="p">=</span><span class="w"> </span><span class="p">_</span><span class="n">import</span><span class="w"> </span><span class="s">&quot;g2&quot;</span><span class="w"> </span><span class="n">public</span><span class="w"> </span><span class="n">reentrant</span><span class="p">:</span><span class="w"> </span><span class="n">unit</span><span class="w"> </span><span class="p">-&gt;</span><span class="w"> </span><span class="n">word</span><span class="w"> </span><span class="n">array</span><span class="p">;</span><span class="w"></span>
  86 <span class="k">val</span><span class="w"> </span><span class="n">a</span><span class="w"> </span><span class="p">=</span><span class="w"> </span><span class="n">g2</span><span class="w"> </span><span class="p">()</span><span class="w"></span>
  87 <span class="k">val</span><span class="w"> </span><span class="p">_</span><span class="w"> </span><span class="p">=</span><span class="w"> </span><span class="n">print</span><span class="w"> </span><span class="p">(</span><span class="n">concat</span><span class="w"> </span><span class="p">[</span><span class="s">&quot;0wx&quot;</span><span class="p">,</span><span class="w"> </span><span class="n">Word</span><span class="p">.</span><span class="n">toString</span><span class="w"> </span><span class="p">(</span><span class="n">Array</span><span class="p">.</span><span class="n">sub</span><span class="w"> </span><span class="p">(</span><span class="n">a</span><span class="p">,</span><span class="w"> </span><span class="mi">0</span><span class="p">)),</span><span class="w"> </span><span class="s">&quot;</span><span class="se">\n</span><span class="s">&quot;</span><span class="p">])</span><span class="w"></span>
  88
  89 <span class="k">val</span><span class="w"> </span><span class="n">e</span><span class="w"> </span><span class="p">=</span><span class="w"> </span><span class="p">_</span><span class="n">export</span><span class="w"> </span><span class="s">&quot;f3&quot;</span><span class="p">:</span><span class="w"> </span><span class="p">(</span><span class="n">unit</span><span class="w"> </span><span class="p">-&gt;</span><span class="w"> </span><span class="n">unit</span><span class="p">)</span><span class="w"> </span><span class="p">-&gt;</span><span class="w"> </span><span class="n">unit</span><span class="p">;</span><span class="w"></span>
  90 <span class="k">val</span><span class="w"> </span><span class="p">_</span><span class="w"> </span><span class="p">=</span><span class="w"> </span><span class="n">e</span><span class="w"> </span><span class="p">(</span><span class="k">fn</span><span class="w"> </span><span class="p">()</span><span class="w"> </span><span class="p">=&gt;</span><span class="w"> </span><span class="n">print</span><span class="w"> </span><span class="s">&quot;hello</span><span class="se">\n</span><span class="s">&quot;</span><span class="p">);</span><span class="w"></span>
  91 <span class="k">val</span><span class="w"> </span><span class="n">g3</span><span class="w"> </span><span class="p">=</span><span class="w"> </span><span class="p">_</span><span class="n">import</span><span class="w"> </span><span class="s">&quot;g3&quot;</span><span class="w"> </span><span class="n">public</span><span class="w"> </span><span class="n">reentrant</span><span class="p">:</span><span class="w"> </span><span class="n">unit</span><span class="w"> </span><span class="p">-&gt;</span><span class="w"> </span><span class="n">unit</span><span class="p">;</span><span class="w"></span>
  92 <span class="k">val</span><span class="w"> </span><span class="p">_</span><span class="w"> </span><span class="p">=</span><span class="w"> </span><span class="n">g3</span><span class="w"> </span><span class="p">()</span><span class="w"></span>
  93
  94 <span class="cm">(* This example demonstrates mutual recursion between C and SML. *)</span><span class="w"></span>
  95 <span class="k">val</span><span class="w"> </span><span class="n">e</span><span class="w"> </span><span class="p">=</span><span class="w"> </span><span class="p">_</span><span class="n">export</span><span class="w"> </span><span class="s">&quot;f4&quot;</span><span class="p">:</span><span class="w"> </span><span class="p">(</span><span class="n">int</span><span class="w"> </span><span class="p">-&gt;</span><span class="w"> </span><span class="n">unit</span><span class="p">)</span><span class="w"> </span><span class="p">-&gt;</span><span class="w"> </span><span class="n">unit</span><span class="p">;</span><span class="w"></span>
  96 <span class="k">val</span><span class="w"> </span><span class="n">g4</span><span class="w"> </span><span class="p">=</span><span class="w"> </span><span class="p">_</span><span class="n">import</span><span class="w"> </span><span class="s">&quot;g4&quot;</span><span class="w"> </span><span class="n">public</span><span class="w"> </span><span class="n">reentrant</span><span class="p">:</span><span class="w"> </span><span class="n">int</span><span class="w"> </span><span class="p">-&gt;</span><span class="w"> </span><span class="n">unit</span><span class="p">;</span><span class="w"></span>
  97 <span class="k">val</span><span class="w"> </span><span class="p">_</span><span class="w"> </span><span class="p">=</span><span class="w"> </span><span class="n">e</span><span class="w"> </span><span class="p">(</span><span class="k">fn</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="p">=&gt;</span><span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="p">=</span><span class="w"> </span><span class="mi">0</span><span class="w"> </span><span class="k">then</span><span class="w"> </span><span class="p">()</span><span class="w"> </span><span class="k">else</span><span class="w"> </span><span class="n">g4</span><span class="w"> </span><span class="p">(</span><span class="n">i</span><span class="w"> </span><span class="n">-</span><span class="w"> </span><span class="mi">1</span><span class="p">))</span><span class="w"></span>
  98 <span class="k">val</span><span class="w"> </span><span class="p">_</span><span class="w"> </span><span class="p">=</span><span class="w"> </span><span class="n">g4</span><span class="w"> </span><span class="mi">13</span><span class="w"></span>
  99
 100 <span class="k">val</span><span class="w"> </span><span class="p">(_,</span><span class="w"> </span><span class="n">zzzSet</span><span class="p">)</span><span class="w"> </span><span class="p">=</span><span class="w"> </span><span class="p">_</span><span class="n">symbol</span><span class="w"> </span><span class="s">&quot;zzz&quot;</span><span class="w"> </span><span class="n">alloc</span><span class="p">:</span><span class="w"> </span><span class="p">(</span><span class="n">unit</span><span class="w"> </span><span class="p">-&gt;</span><span class="w"> </span><span class="n">int</span><span class="p">)</span><span class="w"> </span><span class="n">*</span><span class="w"> </span><span class="p">(</span><span class="n">int</span><span class="w"> </span><span class="p">-&gt;</span><span class="w"> </span><span class="n">unit</span><span class="p">);</span><span class="w"></span>
 101 <span class="k">val</span><span class="w"> </span><span class="p">()</span><span class="w"> </span><span class="p">=</span><span class="w"> </span><span class="n">zzzSet</span><span class="w"> </span><span class="mi">42</span><span class="w"></span>
 102 <span class="k">val</span><span class="w"> </span><span class="n">g5</span><span class="w"> </span><span class="p">=</span><span class="w"> </span><span class="p">_</span><span class="n">import</span><span class="w"> </span><span class="s">&quot;g5&quot;</span><span class="w"> </span><span class="n">public</span><span class="p">:</span><span class="w"> </span><span class="n">unit</span><span class="w"> </span><span class="p">-&gt;</span><span class="w"> </span><span class="n">unit</span><span class="p">;</span><span class="w"></span>
 103 <span class="k">val</span><span class="w"> </span><span class="p">_</span><span class="w"> </span><span class="p">=</span><span class="w"> </span><span class="n">g5</span><span class="w"> </span><span class="p">()</span><span class="w"></span>
 104
 105 <span class="k">val</span><span class="w"> </span><span class="p">_</span><span class="w"> </span><span class="p">=</span><span class="w"> </span><span class="n">print</span><span class="w"> </span><span class="s">&quot;success</span><span class="se">\n</span><span class="s">&quot;</span><span class="w"></span>
 106 </pre></div></div></div>
 107 <div class="paragraph"><p>Note that the the <span class="monospaced">reentrant</span> attribute is used for <span class="monospaced">_import</span>-ing the
 108 C functions that will call the <span class="monospaced">_export</span>-ed SML functions.</p></div>
 109 <div class="paragraph"><p>Create the header file with <span class="monospaced">-export-header</span>.</p></div>
 110 <div class="listingblock">
 111 <div class="content monospaced">
 112 <pre>% mlton -default-ann 'allowFFI true'    \
 113         -export-header export.h         \
 114         -stop tc                        \
 115         export.sml</pre>
 116 </div></div>
 117 <div class="paragraph"><p><span class="monospaced">export.h</span> now contains the following C prototypes.</p></div>
 118 <div class="listingblock">
 119 <div class="content monospaced">
 120 <pre>Int8 f (Int32 x0, Real64 x1, Int8 x2);
 121 Pointer f2 (Word8 x0);
 122 void f3 ();
 123 void f4 (Int32 x0);
 124 extern Int32 zzz;</pre>
 125 </div></div>
 126 <div class="paragraph"><p>Use <span class="monospaced">export.h</span> in a C program, <span class="monospaced">ffi-export.c</span>, as follows.</p></div>
 127 <div class="listingblock">
 128 <div class="content"><div class="highlight"><pre><span class="cp">#include</span> <span class="cpf">&lt;stdio.h&gt;</span><span class="cp"></span>
 129 <span class="cp">#include</span> <span class="cpf">&quot;export.h&quot;</span><span class="cp"></span>
 130
 131 <span class="cm">/* Functions in C are by default PUBLIC symbols */</span>
 132 <span class="kt">void</span> <span class="nf">g</span> <span class="p">()</span> <span class="p">{</span>
 133         <span class="n">Char8</span> <span class="n">c</span><span class="p">;</span>
 134
 135         <span class="n">fprintf</span> <span class="p">(</span><span class="n">stderr</span><span class="p">,</span> <span class="s">&quot;g starting</span><span class="se">\n</span><span class="s">&quot;</span><span class="p">);</span>
 136         <span class="n">c</span> <span class="o">=</span> <span class="n">f</span> <span class="p">(</span><span class="mi">13</span><span class="p">,</span> <span class="mf">17.15</span><span class="p">,</span> <span class="sc">&#39;a&#39;</span><span class="p">);</span>
 137         <span class="n">fprintf</span> <span class="p">(</span><span class="n">stderr</span><span class="p">,</span> <span class="s">&quot;g done  char = %c</span><span class="se">\n</span><span class="s">&quot;</span><span class="p">,</span> <span class="n">c</span><span class="p">);</span>
 138 <span class="p">}</span>
 139
 140 <span class="n">Pointer</span> <span class="nf">g2</span> <span class="p">()</span> <span class="p">{</span>
 141         <span class="n">Pointer</span> <span class="n">res</span><span class="p">;</span>
 142         <span class="n">fprintf</span> <span class="p">(</span><span class="n">stderr</span><span class="p">,</span> <span class="s">&quot;g2 starting</span><span class="se">\n</span><span class="s">&quot;</span><span class="p">);</span>
 143         <span class="n">res</span> <span class="o">=</span> <span class="n">f2</span> <span class="p">(</span><span class="mh">0xFF</span><span class="p">);</span>
 144         <span class="n">fprintf</span> <span class="p">(</span><span class="n">stderr</span><span class="p">,</span> <span class="s">&quot;g2 done</span><span class="se">\n</span><span class="s">&quot;</span><span class="p">);</span>
 145         <span class="k">return</span> <span class="n">res</span><span class="p">;</span>
 146 <span class="p">}</span>
 147
 148 <span class="kt">void</span> <span class="nf">g3</span> <span class="p">()</span> <span class="p">{</span>
 149         <span class="n">fprintf</span> <span class="p">(</span><span class="n">stderr</span><span class="p">,</span> <span class="s">&quot;g3 starting</span><span class="se">\n</span><span class="s">&quot;</span><span class="p">);</span>
 150         <span class="n">f3</span> <span class="p">();</span>
 151         <span class="n">fprintf</span> <span class="p">(</span><span class="n">stderr</span><span class="p">,</span> <span class="s">&quot;g3 done</span><span class="se">\n</span><span class="s">&quot;</span><span class="p">);</span>
 152 <span class="p">}</span>
 153
 154 <span class="kt">void</span> <span class="nf">g4</span> <span class="p">(</span><span class="n">Int32</span> <span class="n">i</span><span class="p">)</span> <span class="p">{</span>
 155         <span class="n">fprintf</span> <span class="p">(</span><span class="n">stderr</span><span class="p">,</span> <span class="s">&quot;g4 (%d)</span><span class="se">\n</span><span class="s">&quot;</span><span class="p">,</span> <span class="n">i</span><span class="p">);</span>
 156         <span class="n">f4</span> <span class="p">(</span><span class="n">i</span><span class="p">);</span>
 157 <span class="p">}</span>
 158
 159 <span class="kt">void</span> <span class="nf">g5</span> <span class="p">()</span> <span class="p">{</span>
 160         <span class="n">fprintf</span> <span class="p">(</span><span class="n">stderr</span><span class="p">,</span> <span class="s">&quot;g5 ()</span><span class="se">\n</span><span class="s">&quot;</span><span class="p">);</span>
 161         <span class="n">fprintf</span> <span class="p">(</span><span class="n">stderr</span><span class="p">,</span> <span class="s">&quot;zzz = %i</span><span class="se">\n</span><span class="s">&quot;</span><span class="p">,</span> <span class="n">zzz</span><span class="p">);</span>
 162         <span class="n">fprintf</span> <span class="p">(</span><span class="n">stderr</span><span class="p">,</span> <span class="s">&quot;g5 done</span><span class="se">\n</span><span class="s">&quot;</span><span class="p">);</span>
 163 <span class="p">}</span>
 164 </pre></div></div></div>
 165 <div class="paragraph"><p>Compile <span class="monospaced">ffi-export.c</span> and <span class="monospaced">export.sml</span>.</p></div>
 166 <div class="listingblock">
 167 <div class="content monospaced">
 168 <pre>% gcc -c ffi-export.c
 169 % mlton -default-ann 'allowFFI true' \
 170          export.sml ffi-export.o</pre>
 171 </div></div>
 172 <div class="paragraph"><p>Finally, run <span class="monospaced">export</span>.</p></div>
 173 <div class="listingblock">
 174 <div class="content monospaced">
 175 <pre>% ./export
 176 g starting
 177 ...
 178 g4 (0)
 179 success</pre>
 180 </div></div>
 181 </div>
 182 </div>
 183 <div class="sect1">
 184 <h2 id="_download">Download</h2>
 185 <div class="sectionbody">
 186 <div class="ulist"><ul>
 187 <li>
 188 <p>
 189 <a href="https://raw.github.com/MLton/mlton/master/doc/examples/ffi/export.sml"><span class="monospaced">export.sml</span></a>
 190 </p>
 191 </li>
 192 <li>
 193 <p>
 194 <a href="https://raw.github.com/MLton/mlton/master/doc/examples/ffi/ffi-export.c"><span class="monospaced">ffi-export.c</span></a>
 195 </p>
 196 </li>
 197 </ul></div>
 198 </div>
 199 </div>
 200 </div>
 201 <div id="footnotes"><hr></div>
 202 <div id="footer">
 203 <div id="footer-text">
 204 </div>
 205 <div id="footer-badges">
 206 </div>
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