Seamless operability between C++11 and Python
Go to file
Jason Rhinelander 391c75447d Update all remaining tests to new test styles
This udpates all the remaining tests to the new test suite code and
comment styles started in #898.  For the most part, the test coverage
here is unchanged, with a few minor exceptions as noted below.

- test_constants_and_functions: this adds more overload tests with
  overloads with different number of arguments for more comprehensive
  overload_cast testing.  The test style conversion broke the overload
  tests under MSVC 2015, prompting the additional tests while looking
  for a workaround.

- test_eigen: this dropped the unused functions `get_cm_corners` and
  `get_cm_corners_const`--these same tests were duplicates of the same
  things provided (and used) via ReturnTester methods.

- test_opaque_types: this test had a hidden dependence on ExampleMandA
  which is now fixed by using the global UserType which suffices for the
  relevant test.

- test_methods_and_attributes: this required some additions to UserType
  to make it usable as a replacement for the test's previous SimpleType:
  UserType gained a value mutator, and the `value` property is not
  mutable (it was previously readonly).  Some overload tests were also
  added to better test overload_cast (as described above).

- test_numpy_array: removed the untemplated mutate_data/mutate_data_t:
  the templated versions with an empty parameter pack expand to the same
  thing.

- test_stl: this was already mostly in the new style; this just tweaks
  things a bit, localizing a class, and adding some missing
  `// test_whatever` comments.

- test_virtual_functions: like `test_stl`, this was mostly in the new
  test style already, but needed some `// test_whatever` comments.
  This commit also moves the inherited virtual example code to the end
  of the file, after the main set of tests (since it is less important
  than the other tests, and rather length); it also got renamed to
  `test_inherited_virtuals` (from `test_inheriting_repeat`) because it
  tests both inherited virtual approaches, not just the repeat approach.
2017-08-05 18:46:22 -04:00
docs Made module_local types take precedence over global types 2017-08-05 11:23:34 -04:00
include/pybind11 overload_cast MSVC 2015 fix 2017-08-05 18:46:22 -04:00
pybind11 python -m pybind11 --includes prints include paths 2017-06-28 11:05:26 +02:00
tests Update all remaining tests to new test styles 2017-08-05 18:46:22 -04:00
tools Fix compatibility of FindPythonLibsNew.cmake and FindPythonLibs.cmake 2017-07-23 03:32:19 +02:00
.appveyor.yml Add Catch framework for testing embedding support and C++-side features 2017-05-28 02:12:24 +02:00
.gitignore add CMake exported interface library and Config detection file 2016-12-13 21:44:19 +01:00
.gitmodules Documentation extraction tool 2015-07-22 01:05:41 +02:00
.readthedocs.yml Fix readthedocs build (#721) 2017-03-12 22:36:48 +01:00
.travis.yml travis-ci: Switch debian:buster build to python 3.6 2017-07-06 13:23:59 -04:00
CMakeLists.txt Add C++ interface for the Python interpreter 2017-05-28 02:12:24 +02:00
CONTRIBUTING.md Minor doc fix: `make test -> make pytest` 2016-08-28 14:26:50 -04:00
ISSUE_TEMPLATE.md Tweak GitHub issue template 2017-06-07 14:00:46 +02:00
LICENSE documentation updates 2016-04-29 10:06:24 +02:00
MANIFEST.in include LICENSE, README.md, CONTRIBUTING.md in pip archive (fixes #512) 2016-11-20 23:21:19 +01:00
README.md Added minimum compiler version assertions 2017-03-19 01:34:16 -03:00
setup.cfg Set maximum line length for Python style checker (#552) 2016-12-13 00:59:28 +01:00
setup.py Add C++ interface for the Python interpreter 2017-05-28 02:12:24 +02:00

pybind11 logo

pybind11 — Seamless operability between C++11 and Python

Documentation Status Documentation Status Gitter chat Build Status Build status

pybind11 is a lightweight header-only library that exposes C++ types in Python and vice versa, mainly to create Python bindings of existing C++ code. Its goals and syntax are similar to the excellent Boost.Python library by David Abrahams: to minimize boilerplate code in traditional extension modules by inferring type information using compile-time introspection.

The main issue with Boost.Python—and the reason for creating such a similar project—is Boost. Boost is an enormously large and complex suite of utility libraries that works with almost every C++ compiler in existence. This compatibility has its cost: arcane template tricks and workarounds are necessary to support the oldest and buggiest of compiler specimens. Now that C++11-compatible compilers are widely available, this heavy machinery has become an excessively large and unnecessary dependency.

Think of this library as a tiny self-contained version of Boost.Python with everything stripped away that isn't relevant for binding generation. Without comments, the core header files only require ~4K lines of code and depend on Python (2.7 or 3.x, or PyPy2.7 >= 5.7) and the C++ standard library. This compact implementation was possible thanks to some of the new C++11 language features (specifically: tuples, lambda functions and variadic templates). Since its creation, this library has grown beyond Boost.Python in many ways, leading to dramatically simpler binding code in many common situations.

Tutorial and reference documentation is provided at http://pybind11.readthedocs.org/en/master. A PDF version of the manual is available here.

Core features

pybind11 can map the following core C++ features to Python

  • Functions accepting and returning custom data structures per value, reference, or pointer
  • Instance methods and static methods
  • Overloaded functions
  • Instance attributes and static attributes
  • Arbitrary exception types
  • Enumerations
  • Callbacks
  • Iterators and ranges
  • Custom operators
  • Single and multiple inheritance
  • STL data structures
  • Iterators and ranges
  • Smart pointers with reference counting like std::shared_ptr
  • Internal references with correct reference counting
  • C++ classes with virtual (and pure virtual) methods can be extended in Python

Goodies

In addition to the core functionality, pybind11 provides some extra goodies:

  • Python 2.7, 3.x, and PyPy (PyPy2.7 >= 5.7) are supported with an implementation-agnostic interface.

  • It is possible to bind C++11 lambda functions with captured variables. The lambda capture data is stored inside the resulting Python function object.

  • pybind11 uses C++11 move constructors and move assignment operators whenever possible to efficiently transfer custom data types.

  • It's easy to expose the internal storage of custom data types through Pythons' buffer protocols. This is handy e.g. for fast conversion between C++ matrix classes like Eigen and NumPy without expensive copy operations.

  • pybind11 can automatically vectorize functions so that they are transparently applied to all entries of one or more NumPy array arguments.

  • Python's slice-based access and assignment operations can be supported with just a few lines of code.

  • Everything is contained in just a few header files; there is no need to link against any additional libraries.

  • Binaries are generally smaller by a factor of at least 2 compared to equivalent bindings generated by Boost.Python. A recent pybind11 conversion of PyRosetta, an enormous Boost.Python binding project, reported a binary size reduction of 5.4x and compile time reduction by 5.8x.

  • When supported by the compiler, two new C++14 features (relaxed constexpr and return value deduction) are used to precompute function signatures at compile time, leading to smaller binaries.

  • With little extra effort, C++ types can be pickled and unpickled similar to regular Python objects.

Supported compilers

  1. Clang/LLVM 3.3 or newer (for Apple Xcode's clang, this is 5.0.0 or newer)
  2. GCC 4.8 or newer
  3. Microsoft Visual Studio 2015 Update 3 or newer
  4. Intel C++ compiler 16 or newer (15 with a workaround)
  5. Cygwin/GCC (tested on 2.5.1)

About

This project was created by Wenzel Jakob. Significant features and/or improvements to the code were contributed by Jonas Adler, Sylvain Corlay, Trent Houliston, Axel Huebl, @hulucc, Sergey Lyskov Johan Mabille, Tomasz Miąsko, Dean Moldovan, Ben Pritchard, Jason Rhinelander, Boris Schäling, Pim Schellart, Ivan Smirnov, and Patrick Stewart.

License

pybind11 is provided under a BSD-style license that can be found in the LICENSE file. By using, distributing, or contributing to this project, you agree to the terms and conditions of this license.