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git-svn-id: https://swig.svn.sourceforge.net/svnroot/swig/trunk/SWIG@490 626c5289-ae23-0410-ae9c-e8d60b6d4f22
99 lines
1.7 KiB
HTML
99 lines
1.7 KiB
HTML
<html>
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<title>SWIG:Examples:python:simple</title>
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<body bgcolor="#ffffff">
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<tt>SWIG/Examples/python/simple/</tt>
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<hr>
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<H2>Simple Python Example</H2>
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<tt>$Header$</tt><br>
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<p>
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This example illustrates how you can hook Python to a very simple C program containing
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a function and a global variable.
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<h2>The C Code</h2>
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Suppose you have the following C code:
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<blockquote>
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<pre>
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/* File : example.c */
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/* A global variable */
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double Foo = 3.0;
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/* Compute the greatest common divisor of positive integers */
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int gcd(int x, int y) {
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int g;
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g = y;
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while (x > 0) {
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g = x;
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x = y % x;
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y = g;
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}
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return g;
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}
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</pre>
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</blockquote>
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<h2>The SWIG interface</h2>
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Here is a simple SWIG interface file:
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<blockquote>
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<pre>
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/* File: example.i */
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%module example
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extern int gcd(int x, int y);
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extern double Foo;
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</pre>
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</blockquote>
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<h2>Compilation</h2>
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<ol>
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<li><tt>swig -python <a href="example.i">example.i</a></tt>
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<p>
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<li>Compile <tt><a href="example_wrap.c">example_wrap.c</a></tt> and <tt><a href="example.c">example.c</a></tt>
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to create the extension <tt>examplemodule.so</tt>.
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</ol>
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<h2>Using the extension</h2>
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Click <a href="example.py">here</a> to see a script that calls our C functions from Python.
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<h2>Key points</h2>
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<ul>
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<li>Use the <tt>import</tt> statement to load your extension module from Python. For example:
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<blockquote>
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<pre>
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import example
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</pre>
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</blockquote>
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<li>C functions work just like Python functions. For example:
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<blockquote>
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<pre>
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g = example.gcd(42,105)
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</pre>
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</blockquote>
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<li>C global variables are accessed through a special variable called 'cvar'. For example:
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<blockquote>
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<pre>
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a = example.cvar.Foo
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</pre>
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</blockquote>
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</ul>
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<hr>
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</body>
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</html>
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