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TestSWIG

SWIG + CSharp samples

Build Status Linux Build status Windows

Structure:

CPP	-> Main library
CSharp -> C++ library proxy (wrapper)
		-> C# Library
		-> C# Tests

Loosely based on CSharpOdeLibrary and my NEC'2015 talk. Requires SWIG 3 installed in your path.

Steps to reproduce:

  • You create C++ library
  • You minimize its interface and build its dll+lib into Build folder
  • You create a SWIG .i wrapper
  • You ran SWIG code generator
  • create a C++ wrapper dll based on generated files, connect it to your library, and build its dll into Build folder
  • create a C# wrapper library based on generated files, and build its dll into Build folder
  • create a C# tests project to test C# library and build it into Build folder

So you shall get:

  • A pure C++ library with no exports (build for all platforms you need)
  • A C++ wrapper library with exports for each language you support, (build for all platforms you need)
  • A library in target language
  • A test case library
  • A bench mark library if required

General Notes:

  • Pure C APIs with C++ backend make development iterations longer.
  • It is important to keep architecture as simple and bare bone C++ as possible.
  • Any standard library object can cause pain in one language or another (like for example std::complex).
  • Minimize header file includes required for your API.
  • Templates require special treatment and are not there in generated wrappers code.
  • Create special target language helper objects that could help integration of your library into users codebase.
  • Configure build order correctly

SWIG .i notes:

  • use %module(directors="1") ModuleName; and %feature("director"); to get inheritance
  • use template specialization alike %template(StateType) std::vector<double>; inside .i file in conjunction with type defenitions alike typedef std::vector<T> StateType; in your C++ interface
  • use %shared_ptr(ClassName) for an object to be passable as shared_ptr, if done correctly Stuff like SWIGTYPE_p_std__shared_ptrT_%TYPE_NAME%_t should not appear - lock for the order
  • In case of shared_ptr use, note that GC collectable objects that inherit from C++ code will be bound to GC rules! Thus if you have a shared_ptr in object B C++ code you must create an object BTargetLanguage that would keep a reference in target language to that shared_ptr (see BSharp implementation and TestWithNew for reference).
  • Write shared_ptr(A) before %feature("director") A;

C++ Notes:

  • Write events/delegates using virtual class functions (no C pointers, std::function's etc)
  • Write Interfaces as pure virtual classes
  • Use single inheritance trees
  • Wrap all non std library objects needed externally

Travis CI Notes:

  • Build Order:
    • Compile Library (C++)
    • Call SWIG (run on .i file)
    • Compile Wrapper Library (C++)
    • Compile Wrapper Library (C#),
    • Compile tests
  • Install mixed enviroment C++ + target language