Apart from writing fast code, one of the main use cases of Cython is
to call external C libraries from Python code. As Cython code
compiles down to C code itself, it is actually trivial to call C
-functions directly in the code. The following describes what needs to
-be done to use an external C library in Cython code.
+functions directly in the code. You may have already seen this in the
+simple tutorial on calling C functions. The following gives a
+complete example for using (and wrapping) an external C library in
+Cython code, including appropriate error handling and considerations
+about designing a suitable API for Python and Cython code.
Imagine you need an efficient way to store integer values in a FIFO
queue. Since memory really matters, and the values are actually