We're pleased to announce the first public release, 0.1 of CFFI, a way to call C from Python.
(This release does not support PyPy yet --- but we announce it here as it is planned for the
next release :-)
The aim of this project is to provide a convenient and reliable way of calling C code from Python.
The interface is based on LuaJIT's FFI and follows a few principles:
- The goal is to call C code from Python. You should be able to do so
without learning a 3rd language: every alternative requires you to learn
their own language (Cython, SWIG) or API (ctypes). So we tried to
assume that you know Python and C and minimize the extra bits of API that
you need to learn.
- Keep all the Python-related logic in Python so that you don't need to
write much C code (unlike CPython native C extensions).
- Work either at the level of the ABI (Application Binary Interface)
or the API (Application Programming Interface). Usually, C
libraries have a specified C API but often not an ABI (e.g. they may
document a "struct" as having at least these fields, but maybe more).
(ctypes works at the ABI level, whereas Cython or native C extensions
work at the API level.)
- We try to be complete. For now some C99 constructs are not supported,
but all C89 should be, including macros (and including macro "abuses",
which you can manually wrap in saner-looking C functions).
- We attempt to support both PyPy and CPython (although PyPy support is not
complete yet) with a reasonable path for other Python implementations like
IronPython and Jython.
- Note that this project is not about embedding executable C code in
Python, unlike Weave. This is about calling existing C libraries
Status of the project
Consider this as a beta release. Creating CPython extensions is fully supported and the API should
be relatively stable; however, minor adjustements of the API are possible.
PyPy support is not yet done and this is a goal for the next release. There are vague plans to make this the
preferred way to call C from Python that can reliably work between PyPy and CPython.
Right now CFFI's verify() requires a C compiler and header files to be available at run-time.
This limitation will be lifted in the near future and it'll contain a way to cache the resulting binary.
Armin Rigo and Maciej Fijałkowski