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8<tt>SWIG/Examples/java/constants/</tt>
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11<H2>Wrapping C Constants</H2>
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13<p>
14When SWIG encounters C preprocessor macros and C declarations that look like constants,
15it creates Java constant with an identical value. Click <a href="example.i">here</a>
16to see a SWIG interface with some constant declarations in it.
17
18
19<h2>Accessing Constants from Java</h2>
20Click <a href="../../../Doc/Manual/Java.html#constants">here</a> for the section on constants in the SWIG and Java documentation.
21<p>
22
23Click <a href="main.java">here</a> to see a Java program that prints out the values
24of the constants contained in the above file.</p>
25<h2>Key points</h2>
26<ul>
27<li>The values of preprocessor macros are converted into Java constants.
28<li>Types are inferred by syntax (e.g., "3" is an integer and "3.5" is a float).
29<li>Character constants such as 'x' are converted into Java strings.
30<li>C string literals such as "Hello World" are converted into Java strings.
31<li>Macros that are not fully defined are simply ignored. For example:
32<blockquote>
33<pre>
34#define EXTERN extern
35</pre>
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37is ignored because SWIG has no idea what type of variable this would be.
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39<p>
40<li>Expressions are allowed provided that all of their components are defined. Otherwise, the constant is ignored.
41
42<li>Certain C declarations involving 'const' are also turned into Java constants.
43<li>The constants that appear in a SWIG interface file do not have to appear in any sort
44of matching C source file since the creation of a constant does not require linkage
45to a stored value (i.e., a value held in a C global variable or memory location).
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