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<h1>Directive #elif</h1>
<hr />
<dl class='group--doc'>
<dt class='head--type'><span class='homogen--type'>Directive</span>
<span class='homogen--name'><b>#elif</b></span>
</dt>
<dd><p><code class='directive'>#if</code><br>
<code class='directive'>#elif</code><br>
<code class='directive'>#elseif</code><br>
<code class='directive'>#else</code><br>
<code class='directive'>#endif</code></p></dd>
<dt class='head--doc'>Description</dt>
<dd class='body--doc'>
<p>The #if directive causes conditional compiling of code depending on
the expression after the #if directive. That is, if the expression
is true, the code up to the next #else, #elif, #elseif or #endif is
compiled. If the expression is false, that code will be skipped.
If the skip leads up to a #else, the code after the else will be
compiled. #elif and #elseif are equivialent and causes the code that
follow them to be compiled if the previous #if or #elif evaluated
false and the expression after the #elif evaluates true.
</p>
<p>Expressions given to #if, #elif or #endif are special, all identifiers
evaluate to zero unless they are defined to something else. Integers,
|
| d8215a | 1996-09-22 | Fredrik Hübinette (Hubbe) | | strings and floats are the only types that can be used, but all pike
|
| a44f22 | 1996-02-24 | Fredrik Hübinette (Hubbe) | | operators can be used on these types.
</p>
|
| d8215a | 1996-09-22 | Fredrik Hübinette (Hubbe) | | <p>Also, two special functions can be used, defined() and constant().
|
| a44f22 | 1996-02-24 | Fredrik Hübinette (Hubbe) | | defined(<identifer>) expands to '1' if the identifier is defined,
|
| d8215a | 1996-09-22 | Fredrik Hübinette (Hubbe) | | '0' otherwise. constant(<identifier>) expands to '1' if identifer is
an predefined constant (with add_constant), '0' otherwise.</p>
|
| a44f22 | 1996-02-24 | Fredrik Hübinette (Hubbe) | | </dd>
<dt class='head--doc'>Example</dt>
<dd class='example'><pre>
<tt><p>#if 1<br />
<dl class='group--doc'><dd>write("foo");<br />
</dd>
</dl>#else<br />
<dl class='group--doc'><dd>write("bar");<br />
</dd>
</dl>#endif<br />
</p>
<p>#if defined(FOO)<br />
<dl class='group--doc'><dd>write(FOO);<br />
</dd>
</dl>#elif defined(BAR)<br />
<dl class='group--doc'><dd>write(BAR);<br />
</dd>
</dl>#else<br />
<dl class='group--doc'><dd>write("default");<br />
</dd>
</dl>#endif<br />
</p>
|
| d8215a | 1996-09-22 | Fredrik Hübinette (Hubbe) | | <p>#if !constant(write_file)<br />
inherit "simulate.pike"<br />
|
| a44f22 | 1996-02-24 | Fredrik Hübinette (Hubbe) | | #endif<br />
<br />
</p>
</tt></pre></dd></dl>
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