Book Image

Learning Cython Programming (Second Edition) - Second Edition

By : Philip Herron
Book Image

Learning Cython Programming (Second Edition) - Second Edition

By: Philip Herron

Overview of this book

Cython is a hybrid programming language used to write C extensions for Python language. Combining the practicality of Python and speed and ease of the C language it’s an exciting language worth learning if you want to build fast applications with ease. This new edition of Learning Cython Programming shows you how to get started, taking you through the fundamentals so you can begin to experience its unique powers. You’ll find out how to get set up, before exploring the relationship between Python and Cython. You’ll also look at debugging Cython, before moving on to C++ constructs, Caveat on C++ usage, Python threading and GIL in Cython. Finally, you’ll learn object initialization and compile time, and gain a deeper insight into Python 3, which will help you not only become a confident Cython developer, but a much more fluent Python developer too.
Table of Contents (14 chapters)
Learning Cython Programming Second Edition
About the Author
About the Reviewer

The public keyword

This is a very powerful keyword in Cython. It allows any cdef declaration with the public modifier to output a respective C/C++ header with the relative declaration accessible from C/C++. For example, we can declare:

cdef public struct CythonStruct:
    size_t number_of_elements;
    char ** elements;

Once the compiler handles this, you will have an output of cython_input.h:

 struct CythonStruct {
    size_t number_of_elements;
    char ** elements;

The main caveat, if you're going to call the Python public declarations directly from C, is that, if your link model is fully embedded and linked against, you need to use some boilerplate code to initialize Python correctly:

#include <Python.h>

int main(int argc, char **argv) {
    Py_Initialize ();
    // code in here
    Py_Finalize ();
    return 0;

And before calling anything with the function, you need to initialize the Python module example if you have a cythonfile.pyx file, and compile it with the...