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Cython
book

Cython

by Kurt W. Smith
January 2015
Intermediate to advanced content levelIntermediate to advanced
254 pages
6h 17m
English
O'Reilly Media, Inc.
Content preview from Cython

Chapter 8. Wrapping C++ Libraries with Cython

There are only two kinds of languages: the ones people complain about and the ones nobody uses.

B. Stroustrup

Using Cython to wrap C++ has much in common with using it to wrap C: we must declare the C or C++ interface we want to wrap in an extern block; we must define Python-accessible functions and extension types that wrap the library; and we must convert Python types to and from C or C++ types when Cython cannot apply automatic conversions.

But C++ is a much larger and more complex language than C. To deal with this added complexity and the additional language constructs, Cython has C++-specific syntax to help.

In this chapter, we will cover all of Cython’s C++ wrapping features. Using them, we will learn how to wrap most C++ constructs in Python.

To get an overview, let’s wrap a simple C++ class from end to end.

Simple Example: MT_RNG Class

To extend our example in Chapter 7, suppose we reimplement our random-number generator in a simple C++ class with the following interface:[14]

namespace mtrandom {

const static unsigned int N = 624;

class MT_RNG {
  public:
    MT_RNG();
    MT_RNG(unsigned long s);
    MT_RNG(unsigned long init_key[], int key_length);

    // initializes RNG state, called by constructors
    void init_genrand(unsigned long s);

    // generates a random number on [0,0xffffffff]-interval
    unsigned long genrand_int32();

    // generates a random number on [0,1]-real-interval
    double genrand_real1();

  private:
    unsigned long mt[N];
    int mti;
}; // class ...
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Publisher Resources

ISBN: 9781491901731Errata PageSupplemental Content