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<title>The GNU Fortran Compiler: PRESENT</title>
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<a name="PRESENT"></a>
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<p>
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Next: <a href="PRODUCT.html#PRODUCT" accesskey="n" rel="next">PRODUCT</a>, Previous: <a href="PRECISION.html#PRECISION" accesskey="p" rel="prev">PRECISION</a>, Up: <a href="Intrinsic-Procedures.html#Intrinsic-Procedures" accesskey="u" rel="up">Intrinsic Procedures</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Option-Index.html#Option-Index" title="Index" rel="index">Index</a>]</p>
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<hr>
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<a name="PRESENT-_002d_002d_002d-Determine-whether-an-optional-dummy-argument-is-specified"></a>
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<h3 class="section">9.210 <code>PRESENT</code> — Determine whether an optional dummy argument is specified</h3>
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<a name="index-PRESENT"></a>
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<dl compact="compact">
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<dt><em>Description</em>:</dt>
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<dd><p>Determines whether an optional dummy argument is present.
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</p>
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</dd>
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<dt><em>Standard</em>:</dt>
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<dd><p>Fortran 95 and later
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</p>
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</dd>
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<dt><em>Class</em>:</dt>
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<dd><p>Inquiry function
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</p>
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</dd>
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<dt><em>Syntax</em>:</dt>
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<dd><p><code>RESULT = PRESENT(A)</code>
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</p>
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</dd>
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<dt><em>Arguments</em>:</dt>
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<dd><table>
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<tr><td width="15%"><var>A</var></td><td width="70%">May be of any type and may be a pointer, scalar or array
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value, or a dummy procedure. It shall be the name of an optional dummy argument
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accessible within the current subroutine or function.</td></tr>
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</table>
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</dd>
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<dt><em>Return value</em>:</dt>
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<dd><p>Returns either <code>TRUE</code> if the optional argument <var>A</var> is present, or
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<code>FALSE</code> otherwise.
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</p>
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</dd>
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<dt><em>Example</em>:</dt>
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<dd><div class="smallexample">
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<pre class="smallexample">PROGRAM test_present
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WRITE(*,*) f(), f(42) ! "F T"
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CONTAINS
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LOGICAL FUNCTION f(x)
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INTEGER, INTENT(IN), OPTIONAL :: x
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f = PRESENT(x)
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END FUNCTION
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END PROGRAM
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</pre></div>
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</dd>
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</dl>
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