SWIG (Simplified Wrapper and Interface Generator)

Version: 4.1.0 (24 Oct 2022)

Tagline: SWIG is a compiler that integrates C and C++ with languages
        including Perl, Python, Tcl, Ruby, PHP, Java, C#, D, Go, Lua,
        Octave, R, Scheme (Guile, MzScheme/Racket), Scilab, Ocaml.
        SWIG can also export its parse tree into XML.

SWIG reads annotated C/C++ header files and creates wrapper code (glue
code) in order to make the corresponding C/C++ libraries available to
the listed languages, or to extend C/C++ programs with a scripting
language.

Up-to-date SWIG related information can be found at

       https://www.swig.org

A SWIG FAQ and other hints can be found on the SWIG Wiki:

       https://github.com/swig/swig/wiki

License
=======
Please see the LICENSE file for details of the SWIG license. For
further insight into the license including the license of SWIG's
output code, please visit

       https://www.swig.org/legal.html

Release Notes
=============
Please see the CHANGES.current file for a detailed list of bug fixes and
new features for the current release. The CHANGES file contains bug fixes
and new features for older versions. A summary of changes in each release
can be found in the RELEASENOTES file.

Documentation
=============
The Doc/Manual directory contains the most recent set of updated
documentation for this release. The documentation is available in
three different formats, each of which contains identical content.
These format are, pdf (Doc/Manual/SWIGDocumentation.pdf), single
page html (Doc/Manual/SWIGDocumentation.html) or multiple page html
(other files in Doc/Manual). Please select your chosen format and
copy/install to wherever takes your fancy.

There is some technical developer documentation available in the
Doc/Devel subdirectory.  This is not necessarily up-to-date, but it
has some information on SWIG internals.

Documentation is also online at https://www.swig.org/doc.html.

Backwards Compatibility
=======================
The developers strive their best to preserve backwards compatibility
between releases, but this is not always possible as the overriding
aim is to provide the best wrapping experience. Where backwards
compatibility is known to be broken, it is clearly marked as an
incompatibility in the CHANGES and CHANGES.current files.

See the documentation for details of the SWIG_VERSION preprocessor
symbol if you have backward compatibility issues and need to use more
than one version of SWIG.

Installation
============
Please read the Doc/Manual/Preface.html#Preface_installation for
full installation instructions for Windows, Unix and Mac OS X
using the release tarball/zip file. The INSTALL file has generic
build and installation instructions for Unix users.
Users wishing to build and install code from Github should
visit https://swig.org/svn.html to obtain the more detailed
instructions required for building code obtained from Github - extra
steps are required compared to building from the release tarball.

Testing
=======
The typical 'make -k check' can be performed on Unix operating systems.
Please read Doc/Manual/Preface.html#Preface_testing for details.

Examples
========
The Examples directory contains a variety of examples of using SWIG
and it has some browsable documentation.  Simply point your browser to
the file "Example/index.html".

The Examples directory also includes Visual C++ project 6 (.dsp) files for
building some of the examples on Windows. Later versions of Visual Studio
will convert these old style project files into a current solution file.

Known Issues
============
There are minor known bugs, details of which are in the bug tracker, see
https://www.swig.org/bugs.html.

Troubleshooting
===============
In order to operate correctly, SWIG relies upon a set of library
files.  If after building SWIG, you get error messages like this,

   $ swig foo.i
   :1. Unable to find 'swig.swg'
   :3. Unable to find 'tcl8.swg'

it means that SWIG has either been incorrectly configured or
installed.  To fix this:

   1.  Make sure you remembered to do a 'make install' and that
       the installation actually worked.  Make sure you have
       write permission on the install directory.

   2.  If that doesn't work, type 'swig -swiglib' to find out
       where SWIG thinks its library is located.

   3.  If the location is not where you expect, perhaps
       you supplied a bad option to configure.  Use
       ./configure --prefix=pathname to set the SWIG install
       location.   Also, make sure you don't include a shell
       escape character such as ~ when you specify the path.

   4.  The SWIG library can be changed by setting the SWIG_LIB
       environment variable.  However, you really shouldn't
       have to do this.

If you are having other troubles, you might look at the SWIG Wiki at
https://github.com/swig/swig/wiki.

Participate!
============
Please report any errors and submit patches (if possible)!  We only
have access to a limited variety of hardware (Linux, Solaris, OS-X,
and Windows). All contributions help.

If you would like to join the SWIG development team or contribute a
language module to the distribution, please contact the swig-devel
mailing list, details at https://www.swig.org/mail.html.


-- The SWIG Maintainers

Below are the changes for the current release.
See the CHANGES file for changes in older releases.
See the RELEASENOTES file for a summary of changes in each release.
Issue # numbers mentioned below can be found on Github. For more details, add
the issue number to the end of the URL: https://github.com/swig/swig/issues/

Version 4.1.0 (24 Oct 2022)
===========================

2022-10-24: wsfulton, AndLLA
           [R] #2386 Fix problems in shared_ptr wrappers where the class names
           were not consistent when using the shared_ptr template or the actual
           underlying type.

2022-10-24: wsfulton
           [R] Add support for special variable replacement in the $typemap()
           special variable macro for R specific typemaps (rtype, rtypecheck,
           scoercein, scoereout).

2022-10-24: wsfulton
           [R] Polymorphism in the wrappers was only working for C++ classes,
           now this works for C++ structs too.

2022-10-19: olly
           [Lua] #2126 Fix type resolution between multiple SWIG-wrapped
           modules.

2022-10-17: wsfulton
           [R] #2385 Add support for std::vector<std::vector<std::string>>.

2022-10-14: murillo128
           [Javascript] #2109 Tweak unsigned long and unsigned long long typemaps
           to create a v8::Number instead of v8::Integer if the value exceeds
           the size of v8::Integer. Note that the v8::Number value will be
           imprecise if the value is > MAX_SAFE_INTEGER.

2022-10-14: olly
           [R] Arrange that destructors of local C++ objects in the wrapper
           function get run on SWIG_fail (which calls Rf_error() which calls
           longjmp()).

2022-10-14: olly
           [Lua] Arrange that destructors of local C++ objects in the wrapper
           function get run on SWIG_fail (which calls lua_error() which calls
           longjmp()).

2022-10-13: wsfulton
           [R] Add missing SWIGTYPE *const& typemaps for supporting pointers
           by const reference.

2022-10-10: wsfulton
           #2160 Fix compile error when using templates with more than one template
           parameter and used as an input parameter in a virtual method in a
           director class (problem affecting most of the scripting languages).

2022-10-10: treitmayr, wsfulton
           [Python, Ruby] #1811 #1823 Fix invalid code generated in some cases when
           returning a pointer or reference to a director-enabled class instance.
           This previously only worked in very simple cases, now return types are
           resolved to fix. A bug in template instantiations using pointers also
           works now.

2022-10-06: wsfulton
           [CFFI] #1966 #2200 Remove code for Common Lisp CFFI.  We dropped support
           for it in SWIG 4.0.0 by disabling it as the first stage. This is the
           final stage for complete removal as there has been no meaningful
           progress to revive it to the status of experimental language.

2022-10-06: olly
           [Python] #2390 Remove deprecated and apparently useless defarg.swg

           The only documentation is in the file itself and describes a Python
           wrapper around the C function defined here, but digging though the
           git history this Python wrapper doesn't seem to have ever actually
           been generated by SWIG.

           This file was also marked as deprecated in 2005.

2022-10-06: wsfulton
           [Java] #2048 Fix quoting for doxygen \image command to quote the output
           file name generated into the html src attribute.

2022-10-05: benjamin-sch
           [Python] added an interpreter counter to fix deinitialization
           issues if multiple subinterpreters are used

2022-10-05: olly, wsfulton
           #672 Add support for parsing C++11 final classes such as:

             class X final {};

           This no longer gives a syntax error.

2022-10-05: wsfulton
           [OCaml] Fix %rename for enum items. Previously the rename had no effect.

2022-10-05: olly
           #1465 Report errors in preprocessor expressions by default

           Until now SWIG quietly ignored such errors unless -Wextra (or -Wall
           which implies -Wextra) was passed, but this is unhelpful as it tends
           to hide genuine problems.  To illustrate this point, enabling this
           warning by default revealed a typo in the preproc_defined.i
           testcase in SWIG's own testsuite.

           If you really don't want to see this warning, you can suppress it
           with command line option -w202 or by using this in your interface
           file:

           %warnfilter(SWIGWARN_PP_EVALUATION);

           Both will work with older versions of SWIG too.

2022-10-04: olly
           #1050 Consistently define SWIG_VERSION both at SWIG-time and in
           the generated wrapper.  Best practice remains to check at SWIG-time
           where possible because that results in smaller generated wrapper
           sources.

           SWIGGO and SWIGJAVASCRIPT are now defined in the generated wrappers
           to match behaviour for all other target languages.

           The undocumented SWIGVERSION macro is no longer defined.

2022-09-29: olly
           #2303 SWIG's internal hash tables now use a better hash function.

           The old hash function only considerd the last five characters
           plus the least significant bit of the last-but-sixth character,
           which as you might guess generated a lot of many-way collisions.

           This change seems to give about a 4% reduction in wallclock time
           for processing li_std_list_wrap.i from the testsuite for Python.
           The hash collision rate for this example drops from 39% to 0!

2022-09-29: wsfulton
           #2303 Type tables are now output in a fixed order whereas previously
           the order may change with any minor input code change. This shouldn't
           affect users except SWIG_TypePrettyName may output a different C/C++
           typedef to a type - it's used mostly for showing errors when the type
           passed to a function is wrong.

2022-09-29: olly
           [PHP] Dynamic class properties are no longer supported by default.

           Historically PHP has supported dynamic class properties and SWIG
           has implemented them too (because we implement the magic __get(),
           __set() and __isset() methods we need to include explicit
           handling).

           PHP 8.2 deprecates dynamic class properties - initially they'll
           warn, and apparently they'll not work by default in PHP 9.0:
           https://wiki.php.net/rfc/deprecate_dynamic_properties

           In PHP code dynamic properties can be enabled for a class by
           marking that class with the attribute `#[AllowDynamicProperties]`.

           To follow this PHP change, in SWIG you now need to specify
           `%feature("php:allowdynamicproperties", 1) Foo;` (or
           `%feature("php:allowdynamicproperties", 1)` to enable it for
           all wrapped classes).  Unknown features are ignored, so you can add
           it unconditionally and it'll work with older SWIG too.

           *** POTENTIAL INCOMPATIBILITY ***

2022-09-19: wsfulton
           #1484 Fixes for class inheritance with the same name in different namespaces
           such as:

             namespace A { class Bar {}; }
             namespace B { template<typename T, typename U> class Bar : public A::Bar {}; }

2022-09-19: wsfulton
           #2316 Remove swig.spec file and srcrpm makefile target. These are very out of date
           and don't seem to be used by RPM based Linux distributions which have their
           own version of swig.spec.

2022-09-17: wsfulton
           [Go, Guile, Racket, Scilab] Add throws typemaps for std::string so that thrown
           string exception messages can be seen.

2022-09-17: wsfulton
           [Racket] Add throws typemaps for char * so that thrown string exception
           messages can be seen from Racket.

2022-09-17: wsfulton
           [Javascript, Octave, R] Improve exceptions for %catches and exception
           specifications for native types. String exception messages are shown as
           the exception message instead of just the type of the exception.

2022-09-17: wsfulton
           Add missing typecheck typemaps for std::auto_ptr and std::unique_ptr to
           fix overloading when using these types.

2022-09-17: wsfulton
           [Guile] Add error checking to SWIGTYPE and SWIGTYPE & in typemaps to prevent
           seg faults when passing #nil to these parameter types.

2022-09-16: wsfulton
           #999 Provide SWIGTYPE MOVE typemaps in swigmove.i for implementing full
           move semantics when passing parameters by value.

2022-08-31: wsfulton
           #999 Improve move semantics when using rvalue references.
           The SWIGTYPE && input typemaps now assume the object has been moved.

           These typemaps have been changed assuming that after the function call,
           the rvalue reference parameter has been moved. The parameter's proxy class
           that owns the C++ object thus has the underlying pointer set to null
           so that the (moved from, but still valid) C++ object cannot be used again
           and the object is additionally deleted.

           *** POTENTIAL INCOMPATIBILITY ***

2022-08-28: wsfulton
           [Octave] SWIG now marshals a C/C++ NULL pointer into the null matrix, [].
           SWIG has always marshalled the null matrix into a NULL pointer; this remains
           and now we have consistency in representing a NULL pointer.

2022-08-26: wsfulton
           [Racket] SWIG now marshals a C/C++ NULL pointer into a null value by calling
           scheme_make_null(), so that scheme's null? is true for a NULL C/C++ pointer value.

2022-08-18: wsfulton
           [Racket] Add support for std::unique_ptr in std_unique_ptr.i.
           Add support for std::auto_ptr in std_auto_ptr.i.

2022-08-13: wsfulton
           [Guile] Add support for std::unique_ptr in std_unique_ptr.i.
           Add support for std::auto_ptr in std_auto_ptr.i.

2022-08-11: wsfulton
           [Lua] Add support for std::unique_ptr in std_unique_ptr.i.
           Add support for std::auto_ptr in std_auto_ptr.i.

2022-08-05: wsfulton
           [D] Fix occasional undefined behaviour with inheritance hierarchies, particularly
           when using virtual inheritance as the pointers weren't correctly upcast from derived
           class to base class when stored in the base's proxy class.

2022-08-05: wsfulton
           [D] Add support for std::unique_ptr in std_unique_ptr.i.
           Add support for std::auto_ptr in std_auto_ptr.i.

2022-08-03: wsfulton
           [Javascript] Add support for std::unique_ptr in std_unique_ptr.i.
           Add support for std::auto_ptr in std_auto_ptr.i.

2022-08-02: wsfulton
           [Octave] Add support for std::unique_ptr in std_unique_ptr.i.
           Add support for std::auto_ptr in std_auto_ptr.i.

2022-08-01: wsfulton
           [Python] Add initialisers for additional members in PyHeapTypeObject
           (builtin mode) for Python-3.11 - _ht_tpname, _spec_cache.

2022-07-30: wsfulton
           C++20 has deprecated std::basic_string<>::reserve() and the C++11 method
           std::basic_string<>::shrink_to_fit() is a replacement that can be used.
           std_string.i and std_wstring.i provided wrappers for reserve with the following
           template instantiations:

             %template(string) std::basic_string<char>;
             %template(wstring) std::basic_string<wchar_t>;

           The reserve method is no longer wrapped, however the shrink_to_fit() method
           can be used as an alternative from the target language (the generated wrappers
           call reserve() instead if C++<=20).

           Note that std::basic_string<>::reserve(size_t n) is still wrapped unchanged.

           *** POTENTIAL INCOMPATIBILITY ***

2022-07-30: wsfulton
           [Tcl] Add support for std::unique_ptr in std_unique_ptr.i.
           Add support for std::auto_ptr in std_auto_ptr.i.

2022-07-27: ZackerySpytz, olly
           #1678 Support parsing C++20 templated lambdas.

2022-07-27: ZackerySpytz, olly
           #1622 Add support for the C++20 spaceship operator (<=>).

2022-07-26: olly
           [Tcl] https://sourceforge.net/p/swig/bugs/977/
           Fix handling of long long on 32-bit platforms.  This fix raises
           SWIG's minimum supported Tcl version to 8.4.0 (which was released
           just under 20 years ago).

2022-07-26: olly
           Fix incorrect operator precedence in preprocessor expressions.

2022-07-25: olly
           Support for C++14 binary integer literals in preprocessor expressions.

2022-07-20: wsfulton
           [C#, Java] Ensure the order of interfaces generated in proxy interfaces for the
           %interface family of macros is the same as that parsed from the bases in C++.

2022-07-20: jicks, Ingener74, olly
           #422 [Python] Fix mishandling of a Python class inheriting from
           multiple SWIG-wrapped director classes.

2022-07-19: wsfulton
           #692 [C#, Java, Perl, Python, Ruby] std::unique_ptr and std::auto_ptr typemaps
           provided for inputs types in std_unique_ptr.i and std_auto_ptr.i.

           Now these smart pointers can be used as input parameters to functions. A proxy
           class instance transfers memory ownership of the underlying C++ object from the
           proxy class to a smart pointer instance passed to the wrapped function.

2022-07-19: jschueller
           [Python] #2314 Drop support for Python 3.2.

2022-07-19: olly
           Remove remaining support code for classic macos, which has not been
           supported by Apple for over 20 years now.

2022-07-12: wsfulton
           #999 Performance optimisation for parameters passed by value that are C++11 movable.
           The C++ wrappers create a temporary variable for a parameter to be passed to a
           function. This is initially default constructed and then copy assigned from the
           instance being passed in from the target language. This is unchanged, however,
           when the temporary variable is passed to the wrapped function, it is now done using
           std::move. If the type is move constructible, the move constructor will be used
           instead of the copy constructor.

2022-07-12: wsfulton
           [Perl] Add std::auto_ptr support in std_auto_ptr.i library file.

2022-07-12: erezgeva
           [Perl] Add std::unique_ptr support in std_unique_ptr.i library file.

2022-07-07: jmarrec
           #1158 #2286 Add basic support for C++11 attributes.  These are now
           crudely ignored by SWIG's parser's tokeniser, which is better that
           failing with a parse error.

2022-07-05: ianlancetaylor
           [Go] #2245 Handle NULL pointers for string* conversions.
           Rearrange generation of director methods and rename
           receiver argument from p to swig_p.

2022-07-03: wsfulton
           #999 Performance optimisation for directors for classes passed by value. The directorin
           typemaps in the director methods now use std::move on the input parameter when
           copying the object from the stack to the heap prior to the callback into the target
           language, thereby taking advantage of move semantics if available.

2022-07-02: wsfulton
           #1722 [C#, Java, Python, Ruby] Add std::unique_ptr support. Ported from std::auto_ptr.
           Use the %unique_ptr(T) macro as follows for usage std::unique_ptr<T>. For example, for
           a class called Klass:

             %include "std_unique_ptr.i"
             %unique_ptr(Klass)

           Support is currently limited to only returning a std::unique_ptr from a function.

2022-06-29: wsfulton
           #999 #1044 Enhance SWIGTYPE "out" typemaps to use std::move when copying
           objects, thereby making use of move semantics when wrapping a function returning
           by value if the returned type supports move semantics.

           Wrapping functions that return move only types 'by value' now work out the box
           without having to provide custom typemaps.

           The implementation removed all casts in the "out" typemaps to allow the compiler to
           appropriately choose calling a move constructor, where possible, otherwise a copy
           constructor. The implementation also required modifying SwigValueWrapper to
           change a cast operator from:

             SwigValueWrapper::operator T&() const;

           to

             #if __cplusplus >=201103L
               SwigValueWrapper::operator T&&() const;
             #else
               SwigValueWrapper::operator T&() const;
             #endif

           This is not backwards compatible for C++11 and later when using the valuewrapper feature
           if a cast is explicitly being made in user supplied "out" typemaps. Suggested change
           in custom "out" typemaps for C++11 and later code:

           1. Try remove the cast altogether to let the compiler use an appropriate implicit cast.
           2. Change the cast, for example, from static_cast<X &> to static_cast<X &&>, using the
              __cplusplus macro if all versions of C++ need to be supported.

           *** POTENTIAL INCOMPATIBILITY ***

2022-06-15: wsfulton
           #2039 Add move assignment operator to SwigValueWrapper used by the
           valuewrapper feature.

2022-06-04: sethrj
           Enhance $typemap to support typemap attributes.

             $typemap(method:attribute, typepattern)

           For example:

             %typemap(cstype, out="object") XClass "XClass"
             %typemap(cscode) BarClass %{
               $typemap(cstype:out, XClass) bar() {
                 return null;
               }

             which expands to

               object bar() {
                 return null;
               }

2022-05-30: wsfulton
           [C#, D] Add new special variable expansion: $imfuncname.
           Expands to the function name called in the intermediary class.

2022-05-30: LindleyF
           [Java] #2042 Add new special variable expansion: $imfuncname.
           Expands to the function name called in the intermediary class.

2022-05-28: jkuebart
           [Java] On some versions of Android, specifically Android 6,
           detaching the current thread from the JVM after every invocation
           causes a memory leak.

           Offer SWIG_JAVA_DETACH_ON_THREAD_END to configure a behaviour
           where the JVM is only detached in the thread destructor.

           See https://developer.android.com/training/articles/perf-jni#threads.

2022-05-27: xypron
           [Python] #2277 Define PY_SSIZE_T_CLEAN macro before #include "Python.h" as
           recommended in Python 3.7 and later.

           To avoid this macro definition, add the following to your interface file so
           that SWIG_NO_PY_SSIZE_T_CLEAN is defined at the beginning of the C++ wrappers:

             %begin %{
             #define SWIG_NO_PY_SSIZE_T_CLEAN
             %}

2022-05-26: rokups
           [C#] #1323 Modify SwigDerivedClassHasMethod for a more efficient director
           implementation when calling virtual methods that are not overridden.

2022-05-15: erezgeva, eiselekd
           [Lua, Perl, Octave, PHP, Tcl] #2275 #2276 #2283 Add argcargv.i library containing
           (int ARGC, char **ARGV) multi-argument typemaps.

           Document this library in Typemaps.html.

2022-05-07: KrisThielemans
           [Python] Fix "too many initializers for 'PyHeapTypeObject'" errors
           using PyPy 3.8 and later.

2022-05-04: wsfulton
           [C#] Add C# wchar_t * director typemaps

2022-04-20: cminyard
           Fix an issue where newlines were not properly generated
           for godirectorin typemaps.  If you have a virtual function
           not assigned to zero, in some cases it won't generate a
           newline and you will see errors:
             example.go:1508:3: expected ';', found swig_r
           when compiling the go code.

           Also add an example of using goin and godirectorin and add
           a test for this situation.

2022-04-29: jason-daly, JerryJoyce, wsfulton
           [C#] #1233 Add wchar_t * and std::wstring Unicode string support on Linux.

2022-04-11: robinst
           #2257 Fix new Ruby 3.2 warning "undefining the allocator of T_DATA
           class swig_runtime_data".

2022-04-07: olly
           #1750 SWIG now recognises and ignores Doxygen group commands `@{` and `@}`.

2022-04-06: wsfulton
           ./configure now enables C++11 and later C++ standards testing by default (when
           running: 'make check').

           The options to control this testing are the same:

             ./configure --enable-cpp11-testing
             ./configure --disable-cpp11-testing

           But the former is now the default and the latter can be used to turn off C++11 and
           later C++ standards testing.

2022-04-06: wsfulton
           [Python] #1635 The "autodoc" feature no longer overrides Doxygen comments
           in the generated docstring.

           If a "docstring" feature is present it will still override a Doxygen comment.
           If the "autodoc" feature is also present, the combined "autodoc" and "docstring"
           will override the Doxygen comment. If no "docstring" is present then the
           "autodoc" feature will not be generated when there is a Doxygen comment.

           This way the "autodoc" feature can be specified and used to provide documentation
           for 'missing' Doxygen comments.

           *** POTENTIAL INCOMPATIBILITY ***

2022-04-01: olly
           Remove undocumented and non-functional -browse command line option.

2022-03-26: eltoder
           [Python] #1684 Use different capsule names with and without -builtin

           Types generated with and without -builtin are not compatible. Mixing
           them in a common type list leads to crashes. Avoid this by using
           different capsule names: "type_pointer_capsule" without -builtin and
           "type_pointer_capsule_builtin" with.

2022-03-25: wsfulton
           The debug command line options that display parse tree nodes
           (-debug-module, -debug-top, -debug-symtabs) now display previously hidden
           linked list pointers which are useful for debugging parse trees.

           Added new command line option -debug-quiet. This suppresses the display
           of most linked list pointers and symbol table pointers in the parse tree nodes.

           The keys in the parse tree node are now shown in alphabetical order.

2022-03-24: wsfulton
           #2244 Fix using declaration in derived class bugs when all the base
           class's overloaded methods were overridden in the derived class -
           fixes "multiply defined" errors.

2022-03-23: wsfulton
           [Python] #1779 The -py3 option is deprecated and now has no effect on the
           code generated. Use of this option results in a deprecated warning.
           The related SWIGPYTHON_PY3 macro that this option defined is no longer generated.

           Note that %pythonnondynamic feature generates a metaclass that works on both
           Python 2 and Python 3.

2022-03-21: wsfulton
           [Python] #1779 pyabc.i for abstract base classes now supports versions of
           Python prior to 3.3 by using the collection module for these older versions.
           Python-3.3 and later continue to use the collections.abc module.
           The -py3 option no longer has any effect on the %pythonabc feature.

2022-03-21: jschueller, jim-easterbrook, wsfulton
           [Python] #2137 C++ static member functions no longer generate a "flattened"
           name in the Python module. For example:

             s = example.Spam()
             s.foo()               # Spam::foo() via an instance
             example.Spam.foo()    # Spam::foo() using class method
             example.Spam_foo()    # Spam::foo() "flattened" name

           The "flattened" name is no longer generated, but can be generated
           by using the new -flatstaticmethod option.

           *** POTENTIAL INCOMPATIBILITY ***

2022-03-18: ianlancetaylor
           [Go] #337 Implement %extend base methods in child classes.

2022-03-17: olly
           [Python] #1779 SWIG's Python test-suite and examples are now
           run with Python 3 by default.  To run them with Python 2, set
           PY2 to a non-empty value, e.g.:

           make check-python-test-suite PY2=1

2022-03-16: olly
           [Go] #683 -intgosize is now optional - if not specified the
           generated C/C++ wrapper code will use ptrdiff_t for intgo and
           size_t for uintgo.

2022-03-15: ianlancetaylor
           [Go] Add typemaps for std::string*.

2022-03-15: ianlancetaylor
           [Go] Don't convert arrays to pointers if there is a "gotype"
           typemap entry.

2022-03-15: ianlancetaylor
           [Go] Add documentation note about Go and C++ exceptions.

2022-03-12: wsfulton
           #1524 %interface family of macros no longer contain the getter/setter
           methods for wrapping variables. The interface only contains
           virtual and non-virtual instance methods, that is, no static methods.
           Enums are also no longer added to the interface (affects Java only where
           they were missing from the proxy class, C# never had them in the interface).

           *** POTENTIAL INCOMPATIBILITY ***

2022-03-12: wsfulton
           #1277 Fixes for the family of %interface macros, %interface,
           %interface_impl and %interface_custom fixes for overloaded methods
           in an inheritance chain.

           When C++ methods are not able to be overloaded in a derived class,
           such as when they differ by just const, or the target language
           parameters types are identical even when the C++ parameter types
           are different, SWIG will ignore one of the overloaded methods with
           a warning. A %ignore is required to explicitly ignore one of the
           overloaded methods to avoid the warning message. Methods added
           in the derived classes due to one of the %interface macros are now
           similarly ignored/not added to the derived class.

           The methods added to the derived classes can now also be modified
           via %feature and %rename.

2022-03-08: ianlancetaylor
           [Go] Treat a nil argument as a NULL pointer.

2022-03-08: ianlancetaylor
           [Go] Add documentation notes about thread local storage.

2022-03-08: olly
           #1006 SWIG now copes with an interface filename specified on the
           command line which contains a closing parenthesis `)`, and more
           generally with attributes to `%include` and `%import` which
           are quoted and contain parentheses.

2022-03-07: Omar Medina
           [Tcl] https://sourceforge.net/p/swig/bugs/1290/
           Fix SWIG_AsWCharPtrAndSize() to actually assign to result
           variable.  It looks like SWIG/Tcl wide character handling is
           currently fundamentally broken except on systems which use wide
           characters as the system encoding, but this should fix wrapping
           functions which take a wide string as a parameter on Microsoft
           Windows.

2022-03-07: olly
           [Javascript] #682 Fix handling of functions which take void*.

2022-03-06: olly
           SWIG should now reliably exit with status 0 if the run was
           successful and status 1 if there was an error (or a warning and
           -Werror was in effect).

           Previously in some situations SWIG would try to exit with the
           status set to the number of errors encountered, but that's
           problematic - for example if there were 256 errors this would
           result in exit status 0 on most platforms.  Also some error
           statuses have special meanings e.g. those defined by <sysexits.h>.
           Also SWIG/Javascript tried to exit with status -1 in a few places
           (which typically results in exit status 255).

2022-03-05: wsfulton
           #1441 Fix using declaration in derived class incorrectly introducing a method
           from a base class when the using declaration is declared before the method
           declaration. Problem occurred when within a namespace and the parameter types
           in the method signatures were not fully qualified.
2022-03-05: ianlancetaylor
           [Go] Treat non-const references as pointers.

2022-03-05: ianlancetaylor
           In SWIG Go testsuite, fail test if "go build" fails.

2022-03-03: olly
           #1901 #2223 SWIG should now always exit cleanly if memory
           allocation fails, including removing any output files created
           during the current run.

           Previously most places in the code didn't check for a NULL return
           from malloc()/realloc()/calloc() at all, typically resulting in
           undefined behaviour; some places used assert() to check for a NULL
           return (which is a misuse of assert() and such checks disappear if
           built with NDEBUG defined leaving us back with undefined
           behaviour).

2022-03-03: olly
           #891 Report errors for typemap attributes without a value
           (previously SWIG segfaulted) and for typemap types with a value
           (previously the value was quietly ignored).

           The old way of specifying a language name in the typemap attributes
           is no longer supported (it has been deprecated for 16 years).

2022-03-02: geographika, wsfulton
           [Python] #1951 Add Python variable annotations support.

           Both function annotations and variable annotations are turned on using the
           "python:annotations" feature. Example:

             %feature("python:annotations", "c");

             struct V {
               float val;
             };

           The generated code contains a variable annotation containing the C float type:

             class V(object):
                 val: "float" = property(_example.V_val_get, _example.V_val_set)
                 ...

           Python 3.5 and earlier do not support variable annotations, so variable
           annotations can be turned off with a "python:annotations:novar" feature flag.
           Example turning on function annotations but not variable annotations globally:

             %feature("python:annotations", "c");
             %feature("python:annotations:novar");

           or via the command line:

             -features python:annotations=c,python:annotations:novar

           *** POTENTIAL INCOMPATIBILITY ***

2022-02-27: wsfulton
           [Python] #735 #1561 Function annotations containing C/C++ types are no longer
           generated when using the -py3 option. Function annotations support has been
           moved to a feature to provide finer grained control. It can be turned on
           globally by adding:

             %feature("python:annotations", "c");

           or by using the command line argument:

             -features python:annotations=c

           Also see entry dated 2022-03-02, regarding variable annotations.

           *** POTENTIAL INCOMPATIBILITY ***

2022-02-26: wsfulton
           #655 #1840 Add new warning WARN_LANG_USING_NAME_DIFFERENT to warn when a
           method introduced by a using declaration in a derived class cannot
           be used due to a conflict in names.

2022-02-24: olly
           #1465 An invalid preprocessor expression is reported as a pair of
           warnings with the second giving a more detailed message from the
           expression evaluator.  Previously SWIG prefixed the second message
           with "Error:" - that was confusing as it's actually only a warning
           by default so we've now dropped this prefix.

           Before:

           x.i:1: Warning 202: Could not evaluate expression '1.2'
           x.i:1: Warning 202: Error: 'Floating point constant in preprocessor expression'

           Now:

           x.i:1: Warning 202: Could not evaluate expression '1.2'
           x.i:1: Warning 202: Floating point constant in preprocessor expression

2022-02-23: olly
           #1384 Fix a preprocessor expression evaluation bug.  A
           subexpression in parentheses lost its string/int type flag and
           instead used whatever type was left in the stack entry from
           previous use.  In practice we mostly got away with this because
           most preprocessor expressions are integer, but it could have
           resulted in a preprocessor expression incorrectly evaluating as
           zero.  If -Wextra was in use you got a warning:

           Warning 202: Error: 'Can't mix strings and integers in expression'

2022-02-21: davidcl
           [Scilab] Improve 5.5.2, 6.0.0 and 6.1.0 support.

           For Scilab 5, long names are reduced to small names preserving the
           class prefix and accessor suffix (get or set).

           For Scilab 6, long names with the class prefix and accessor suffix
           should be used on the user code.

           The `-targetversion` option has been removed as the generated code
           now detects the Scilab version in loader.sce or builder.sce.

           *** POTENTIAL INCOMPATIBILITY ***

2022-02-20: wsfulton
           Fix %warnfilter warning suppress for warning 315 SWIGWARN_PARSE_USING_UNDEF.

2022-02-17: olly
           [PHP] https://sourceforge.net/p/swig/bugs/1211/
           Fix to call cleanup code in exception situations and not to invoke
           the freearg typemap twice in certain situations.

2022-02-15: olly
           #300 #368 Improve parser handling of % followed immediately by
           an identifier.  If it's not a recognised directive the scanner
           now emits MODULO and then rescans what follows, and if the parser
           then gives a syntax error we report it as an unknown directive.
           This means that `a%b` is now allowed in an expression, and that
           things like `%std::vector<std::string>` now give an error rather
           than being quietly ignored.

2022-02-11: adr26
           [Python] #2154 Fix memory leak.

           SWIG python objects were being freed after the corresponding SWIG
           module information was destroyed in Python 3, causing leaks when as
           a result the object destructor could not be invoked. To prevent this
           misordering, SWIG python objects now obtain a reference to the
           Python capsule wrapping the module information, so that the module
           information is correctly destroyed after all SWIG python objects
           have been freed (and corresponding destructors invoked).

2022-02-10: olly
           [Tcl] https://sourceforge.net/p/swig/bugs/1207/
           https://sourceforge.net/p/swig/bugs/1213/

           Fix Tcl generic input typemap for std::vector.

2022-02-07: sethrj
           #2196 Add alternative syntax for specifying fragments in typemaps.

           New syntax:
             %typemap("in", fragment="frag1", fragment="frag2", fragment="frag3") {...}
           which is equivalent to:
             %typemap(in, fragment="frag1,frag2,frag3") {...}


2022-02-07: olly
           #1806 Remove support for the "command" encoder, which was mostly
           intended for use in `%rename` - most uses can be achieved using
           the "regex" encoder, so we recommend using that instead.

           The "command" encoder suffers from a number of issues - as the
           documentation for it admitted, "[it] is extremely slow compared to
           all the other [encoders] as it involves spawning a separate process
           and using it for many declarations is not recommended" and that it
           "should generally be avoided because of performance
           considerations".

           But it's also not portable.  The design assumes that `/bin/sh`
           supports `<<<` but that's a bash-specific feature so it doesn't
           work on platforms where `/bin/sh` is not bash - it fails on
           Debian, Ubuntu and probably some other Linux distros, plus most
           non-Linux platforms.  Microsoft Windows doesn't even have a
           /bin/sh as standard.

           Finally, no escaping of the passed string is done, so it has
           potential security issues (though at least with %rename the input
           is limited to valid C/C++ symbol names).

2022-02-06: olly
           #2193 -DFOO on the SWIG command line now sets FOO to 1 for
           consistency with C/C++ compiler preprocessors.  Previously
           SWIG set FOO to an empty value.

           Existing invocations of SWIG with `-DFOO` where the empty value
           matters can be updated to `-DFOO=` which should work with both
           old and new releases of SWIG.

           *** POTENTIAL INCOMPATIBILITY ***

2022-02-06: sethrj
           #2194 Classes that are non-assignable due to const data or const
           reference members are now automatically detected.

2022-02-04: friedrichatgc
           [Octave] #1672 Fix for isobject for Octave 4.4 - 6.0.

2022-02-03: olly
           [C#] #283 #998 Fix memory leak in directorin typemap for
           std::string.

2022-02-03: olly
           [Python] #967 Make `self` parameter available to user typemaps.

2022-02-03: teythoon
           [Python] #801 Fix -Wunused-parameter warnings with builtin,

2022-02-03: teythoon
           #801 Fix -Wstrict-prototypes warnings in generated pointer
           functions.

2022-02-03: olly
           #660 https://sourceforge.net/p/swig/bugs/1081/
           Default parameter values containing method calls are now parsed and
           handled - e.g. `x->foo(3,4)` and `y.z()`.

2022-02-02: olly
           [Ruby] https://sourceforge.net/p/swig/bugs/1136/ Fix remove of prefix
           from method name to only remove it at the start.

2022-02-01: olly
           #231 Handle returning an object by reference in a C++ trailing
           return type.

2022-02-01: davidcl
           [Scilab] #745 use SWIG_<module>_Init() as a C module init function.

2022-02-01: olly
           [OCaml] #2083 Fix to work when CAML_SAFE_STRING is on, which it is
           by default in recent Ocaml releases.

2022-01-31: mreeez
           https://sourceforge.net/p/swig/bugs/1147/
           Fix copyToR() generated for a struct in a namespace.

2022-01-29: fschlimb
           #655 Better handling of using declarations.

2022-01-29: dontpanic92
           [Go] #676 Fix code generated for a C++ class with a non-capitalised
           name.

2022-01-26: trex58
           #1919 #1921 #1923 Various fixes for AIX portability.

2022-01-26: olly
           #1935 Don't crash on an unclosed HTML tag in a doxygen comment
           when -doxygen is specified.

2022-01-25: olly
           Constant expressions now support member access with `.` such as
           `foo.bar`.  Previous this only worked in a case like `x->foo.bar`.

2022-01-25: olly
           #2091 Support most cases of `sizeof` applied to an expression
           in constant expressions.  Previously there was only support for
           `sizeof(<type>)` and expressions which syntactically look like a
           type (such as `sizeof(foo)`).

2022-01-25: olly
           #80 #635 https://sourceforge.net/p/swig/bugs/1139/
           Add support for parsing common cases of `<` and `>` comparisons
           in constant expressions.  Adding full support for these seems hard
           to do without introducing conflicts into the parser grammar, but in
           fact all reported cases have had parentheses around the comparison
           and we can support that with a few restrictions on the left side of
           `<`.

2022-01-25: wsfulton
           New warning 327 for extern templates, eg:

             extern template class std::vector<int>;
             extern template void Func<int>();

           results in warning

             example.i:3: Warning 327: Extern template ignored.
             example.i:4: Warning 327: Extern template ignored.

           Extern template classes previously resulted in warning 320.

2022-01-24: romintomasetti
           #2131 #2157 C++11 extern function template parsing error fix.

2022-01-21: wsfulton
           #2120 #2138 Replace legacy PCRE dependency with PCRE2.
           This requires changes for building SWIG from source. See updated
           html documentation in Preface.html and Windows.html. Updated
           instructions are also shown when running ./configure if PCRE2 is not
           found. Note that debian based systems can install PCRE2 using:

             apt install libpcre2-dev

           Note that https://github.com/swig/swig/wiki/Getting-Started also has
           updated information for building from source.

2022-01-19: olly
           [PHP] #2027 Automatically generate PHP type declarations for PHP 8.
           The generate code still compiles for PHP 7.x, but without type
           declarations since PHP 7.x has much more limited type declaration
           support.

2022-01-18: olly
           [Perl] #1629 Perl 5.8.0 is now the oldest version we aim to support.

2022-01-14: wsfulton
           [Python] Fix %callback and specifying the callback function as a
           static member function using Python staticmethod syntax, such as
           Klass.memberfunction instead of Klass_memberfunction when using
           -builtin and -fastproxy.

2022-01-11: wsfulton
           [Python] Accept keyword arguments accessing static member functions when
           using -builtin and kwargs feature and Python class staticmethod syntax.
           The missing keyword argument support was only when using the
           class staticmethod syntax, such as Klass.memberfunction, and not when
           using the flat static method syntax, such as Klass_memberfunction.

2022-01-04: juierror
           [Go] #2045 Add support for std::array in std_array.i.

2021-12-18: olly
           [PHP] Add PHP keyword 'readonly' (added in 8.1) to the list SWIG
           knows to automatically rename.  This keyword is special in that PHP
           allows it to be used as a function (or method) name.

2021-12-07: vstinner
           [Python] #2116 Python 3.11 support: use Py_SET_TYPE()

2021-12-05: rwf1
           [Octave] #2020 #1893 Add support for Octave 6 up to and including 6.4.
           Also add support for compiling with -Bsymbolic which is used by default
           by mkoctfile.

2021-12-02: jsenn
           [Python] #2102 Fixed crashes when using embedded Python interpreters.

2021-11-12: wsfulton
           [Javascript] v8 and node only. Fix mismatched new char[] and free()
           when wrapping C code char arrays. Now calloc is now used instead of
           new char[] in SWIG_AsCharPtrAndSize.

2021-10-03: ajrh1
           [Perl] #2074: Avoid -Wmisleading-indentation in generated code
           when using gcc11.

2021-10-03: jschueller
           [CMake] #2065: Add option to enable or disable PCRE support.

2021-09-16: ianlancetaylor
           [Go] Improved _cgo_panic implementation.

2021-09-16: ianlancetaylor
           [Go] Don't use crosscall2 for panicking. Instead rely on documented
           and exported interfaces.

2021-09-14: ianlancetaylor
           [Go] Remove -no-cgo option (long unsupported in Go)

2021-05-04: olly
           [PHP] #2014 Throw PHP exceptions instead of using PHP errors

           PHP exceptions can be caught and handled if desired, but if they
           aren't caught then PHP exits in much the same way as it does for a
           PHP error.

           In particular this means parameter type errors and some other cases
           in SWIG-generated wrappers now throw a PHP exception, which matches
           how PHP's native parameter handling deals with similar situations.

           `SWIG_ErrorCode()`, `SWIG_ErrorMsg()`, `SWIG_FAIL()` and `goto thrown;`
           are no longer supported (these are really all internal implementation
           details and none are documented aside from brief mentions in CHANGES
           for the first three).  I wasn't able to find any uses in user interface
           files at least in FOSS code via code search tools.

           If you are using these:

           Use `SWIG_PHP_Error(code,msg);` instead of `SWIG_ErrorCode(code);
           SWIG_ErrorMsg(msg);` (which will throw a PHP exception in SWIG >= 4.1
           and do the same as the individual calls in older SWIG).

           `SWIG_FAIL();` and `goto thrown;` can typically be replaced with
           `SWIG_fail;`.  This will probably also work with older SWIG, but
           please test with your wrappers if this is important to you.

           *** POTENTIAL INCOMPATIBILITY ***

2021-05-17: adr26
           [Python] #1985 Fix memory leaks:

           1. Python object references were being incorrectly retained by
           SwigPyClientData, causing swig_varlink_dealloc() never to run / free
           memory. SwigPyClientData_New() / SwigPyClientData_Del() were updated
           to fix the object reference counting, causing swig_varlink_dealloc()
           to run and the memory swig_varlink owns to be freed.

           2. SwigPyClientData itself was not freed by SwigPyClientData_Del(),
           causing another heap leak. The required free() was added to
           SwigPyClientData_Del()

           3. Fix reference counting/leak of python cached type query

           4. Fix reference counting/leak of SwigPyObject dict (-builtin)

           5. Python object reference counting fixes for out-of-memory
           scenarios were added to: SWIG_Python_RaiseOrModifyTypeError(),
           SWIG_Python_AppendOutput(), SwigPyClientData_New(),
           SwigPyObject_get___dict__() and SwigPyObject_format()

           6. Add error handling for PyModule_AddObject() to
           SWIG_Python_SetModule() (failure could be caused by OOM or a name
           clash caused by malicious code)

2021-05-13: olly
           [UFFI] #2009 Remove code for Common Lisp UFFI.  We dropped support
           for it in SWIG 4.0.0 and nobody has stepped forward to revive it in
           over 2 years.

2021-05-13: olly
           [S-EXP] #2009 Remove code for Common Lisp S-Exp.  We dropped
           support for it in SWIG 4.0.0 and nobody has stepped forward to
           revive it in over 2 years.

2021-05-13: olly
           [Pike] #2009 Remove code for Pike.  We dropped support for it in
           SWIG 4.0.0 and nobody has stepped forward to revive it in over 2
           years.

2021-05-13: olly
           [Modula3] #2009 Remove code for Modula3.  We dropped support for it
           in SWIG 4.0.0 and nobody has stepped forward to revive it in over 2
           years.

2021-05-13: olly
           [CLISP] #2009 Remove code for GNU Common Lisp.  We dropped support
           for it in SWIG 4.0.0 and nobody has stepped forward to revive it in
           over 2 years.

2021-05-13: olly
           [Chicken] #2009 Remove code for Chicken.  We dropped support for it
           in SWIG 4.0.0 and nobody has stepped forward to revive it in over 2
           years.

2021-05-13: olly
           [Allegrocl] #2009 Remove code for Allegro Common Lisp.  We dropped
           support for it in SWIG 4.0.0 and nobody has stepped forward to
           revive it in over 2 years.

2021-05-04: olly
           [PHP] #1982 #1457 https://sourceforge.net/p/swig/bugs/1339/
           SWIG now only use PHP's C API to implement its wrappers, and no
           longer generates PHP code to define classes.  The wrappers should
           be almost entirely compatible with those generated before, but
           faster and without some previously hard-to-fix bugs.

           The main notable difference is SWIG no longer generates a .php
           wrapper at all by default (only if %pragma(php) code=... or
           %pragma(php) include=... are specified in the interface file).
           This also means you need to load the module via extension=...
           in php.ini, rather than letting the dl() in the generated
           .php wrapper load it (but dl() has only worked for command-line
           PHP for some years now).

           *** POTENTIAL INCOMPATIBILITY ***

2021-04-30: olly
           #1984 Remove support for $source and $target.
           These were officially deprecated in 2001, and attempts to use them have
           resulted in a warning (including a pointer to what to update them to)
           for most if not all of that time.

2021-04-27: wsfulton
           #1987 [Java] Fix %interface family of macros for returning by const
           pointer reference.

2021-04-19: olly
           Fix use of uninitialised variable in the generated code for an
           empty typecheck typemap, such as the dummy one we include for
           std::initializer_list.

2021-04-12: olly
           #1777 [Python] Specifying -py3 now generates a check for Python
           version >= 3.0.

2021-03-26: olly
           [PHP] Add PHP keywords 'fn' (added in 7.4) and 'match' (added in
           8.0) to the list SWIG knows to automatically rename.

2021-03-23: wsfulton
           #1942 [Python] Fix compilation error in wrappers when using -builtin
           and wrapping varargs in constructors.

2021-03-22: goto40
           #1977 Fix handling of template template parameters.

2021-03-21: olly
           #1929, #1978 [PHP] Add support for PHP 8.

2021-03-19: wsfulton
           #1610 Remove -ansi from default compilation flags.

2021-03-19: dot-asm
           #1934 [Java] Clean up typemaps for long long arrays.

2021-03-19: olly
           #1527 [PHP] Improve PHP object creation in directorin case.
           Reportedly the code we were using in this case gave segfaults in
           PHP 7.2 and later - we've been unable to reproduce these, but the
           new approach is also simpler and should be bit faster too.

2021-03-18: olly
           #1655 [PHP] Fix char* typecheck typemap to accept PHP Null like the
           corresponding in typemap does.

2021-03-18: olly
           #1900, #1905 [PHP] Fix wrapping of overloaded directed methods with
           non-void return.

2021-03-11: murillo128
           #1498 [Javascript] Support type conversion.

2021-03-06: nshmyrev
           #872 [Javascript] Various typemap issues in arrays_javascript.i fixed.

2021-03-03: vaughamhong
           #577 [Javascript] Implemented SetModule/GetModule for JSC to allow type sharing
           across modules.

2021-03-01: xantares, Oliver Buchtala, geographika
           #1040 Add support for building SWIG with CMake. See documentation in Windows.html.

2021-03-01: vadz
           #1952 Fix incorrect warning "Unknown Doxygen command: ."

2021-02-28: p2k
           #969 [Javascript] v8/node - prevent crash calling a constructor without new keyword.

2021-02-28: alecmev
           #405 #1121 [Javascript] Fix OUTPUT typemaps on methods that don't return void.
           The output value is appended to the return value.

2021-02-26: murillo128, wsfulton
           #1269 [Javascript] Fix handling of large positive unsigned long and
           unsigned long long values.

2021-02-24: tomleavy, yegorich, tungntpham
           #1746 [Javascript] Add support for Node v12, v14 and v16.
           SWIG support for Node is now for v6 and later only.

2020-02-09: ZackerySpytz
           #1872 Fix typos in attribute2ref macros.

2020-10-10: wsfulton
           [Javascript] Fix so that ccomplex.i interface to file can be used.

2020-10-10: wsfulton
           #252 complex can now be used as a C identifier and doesn't give a syntax error.

2020-10-10: lpsinger
           #1770 Correct C complex support.
           _Complex is now parsed as a keyword rather than complex as per the C99 standard.
           The complex macro is available in the ccomplex.i library file along with other
           complex number handling provided by the complex.h header.

2020-10-07: ZackerySpytz
           [Python] #1812 Fix the error handling for the PyObject_GetBuffer() calls in
           pybuffer.i.

2020-10-07: treitmayr
           #1824 Add missing space in director method declaration returning
           const pointer.

2020-10-07: adelva1984
           #1859 Remove all (two) exceptions from SWIG executable.

2020-09-25: wsfulton
           [C#, Java] #1874 Add ability to change the modifiers for the interface
           generated when using the %interface macros.

           For C# use the 'csinterfacemodifiers' typemap.
           For Java use the 'javainterfacemodifiers' typemap.

           For example:

             %typemap(csinterfacemodifiers) X "internal interface"

2020-09-24: geefr
           [C#] #1868 Fix wchar_t* csvarout typemap for member variable wrappers.

2020-08-28: wsfulton
           [Java] #1862 Fix crashes in swig_connect_director during director class construction
           when using the director class from multiple threads - a race condition initialising
           block scope static variables. The fix is guaranteed when using C++11, but most
           compilers also fix it when using C++03/C++98.

2020-08-16: wsfulton
           [Python] Add missing initializer for member ‘_heaptypeobject::ht_module’ when using
           -builtin to complete Python 3.9 support.

2020-08-16: wsfulton
           [Python] Remove PyEval_InitThreads() call for Python 3.7 and later as Python calls
           it automatically now. This removes a deprecation warning when using Python 3.9.

2020-08-15: wsfulton
           [Python] All Python examples and tests are written to be Python 2 and Python 3
           compatible, removing the need for 2to3 to run the examples or test-suite.

2020-08-13: wsfulton
           [C#] Add support for void *VOID_INT_PTR for member variables.

2020-07-29: chrisburr
           #1843 [Python] Compilation error fix in SwigPyBuiltin_SetMetaType when using PyPy.

2020-06-14: ZackerySpytz
           #1642 #1809 Fix virtual comparison operators in director classes by removing an
           incorrect space in the function name (for example, operator= = is now operator==).
This file contains a brief overview of the changes made in each release.
A detailed description of changes are available in the CHANGES.current
and CHANGES files.

Release Notes
=============
Detailed release notes are available with the release and are also
published on the SWIG web site at https://swig.org/release.html.

SWIG-4.1.0 summary:
- Add Javascript Node v12-v18 support, remove support prior to v6.
- Octave 6.0 to 6.4 support added.
- Add PHP 8 support.
- PHP wrapping is now done entirely via PHP's C API - no more .php wrapper.
- Perl 5.8.0 is now the oldest version SWIG supports.
- Python 3.3 is now the oldest Python 3 version SWIG supports.
- Python 3.9-3.11 support added.
- Various memory leak fixes in Python generated code.
- Scilab 5.5-6.1 support improved.
- Many improvements for each and every target language.
- Various preprocessor expression handling improvements.
- Improved C99, C++11, C++14, C++17 support. Start adding C++20 standard.
- Make SWIG much more move semantics friendly.
- Add C++ std::unique_ptr support.
- Few minor C++ template handling improvements.
- Various C++ using declaration fixes.
- Few fixes for handling Doxygen comments.
- GitHub Actions is now used instead of Travis CI for continuous integration.
- Add building SWIG using CMake as a secondary build system.
- Update optional SWIG build dependency for regex support from PCRE to PCRE2.

SWIG-4.0.2 summary:
- A few fixes around doxygen comment handling.
- Ruby 2.7 support added.
- Various minor improvements to C#, D, Java, OCaml, Octave, Python,
 R, Ruby.
- Considerable performance improvement running SWIG on large
 interface files.

SWIG-4.0.1 summary:
- SWIG now cleans up on error by removing all generated files.
- Add Python 3.8 support.
- Python Sphinx compatibility added for Doxygen comments.
- Some minor regressions introduced in 4.0.0 were fixed.
- Fix some C++17 compatibility problems in Python and Ruby generated
 code.
- Minor improvements/fixes for C#, Java, Javascript, Lua, MzScheme,
 Ocaml, Octave and Python.

SWIG-4.0.0 summary:
- Support for Doxygen documentation comments which are parsed and
 converted into JavaDoc or PyDoc comments.
- STL wrappers improved for C#, Java and Ruby.
- C++11 STL containers added for Java, Python and Ruby.
- Improved support for parsing C++11 and C++14 code.
- Various fixes for shared_ptr.
- Various C preprocessor corner case fixes.
- Corner case fixes for member function pointers.
- Python module overhaul by simplifying the generated code and turning
 most optimizations on by default.
- %template improvements wrt scoping to align with C++ explicit
 template instantiations.
- Added support for a command-line options file (sometimes called a
 response file).
- Numerous enhancements and fixes for all supported target languages.
- SWIG now classifies the status of target languages into either
 'Experimental' or 'Supported' to indicate the expected maturity
 level.
- Support for CFFI, Allegrocl, Chicken, CLISP, S-EXP, UFFI, Pike,
 Modula3 has been removed.
- Octave 4.4-5.1 support added.
- PHP5 support removed, PHP7 is now the supported PHP version.
- Minimum Python version required is now 2.7, 3.2-3.7 are the only
 other versions supported.
- Added support for Javascript NodeJS versions 2-10.
- OCaml support is much improved and updated, minimum OCaml version
 required is now 3.12.0.

SWIG-3.0.12 summary:
- Add support for Octave-4.2.
- Enhance %extend to support template functions.
- Language specific enhancements and fixes for C#, D, Guile, Java, PHP7.

SWIG-3.0.11 summary:
- PHP 7 support added.
- C++11 alias templates and type aliasing support added.
- Minor fixes and enhancements for C# Go Guile Java Javascript Octave
 PHP Python R Ruby Scilab XML.

SWIG-3.0.10 summary:
- Regression fixes for smart pointers and importing Python modules.

SWIG-3.0.9 summary:
- Add support for Python's implicit namespace packages.
- Fixes to support Go 1.6.
- C++11 std::array support added for Java.
- Improved C++ multiple inheritance support for Java/C# wrappers.
- Various other minor fixes and improvements for C#, D, Go, Java,
 Javascript, Lua, Python, R, Ruby, Scilab.

SWIG-3.0.8 summary:
- pdf documentation enhancements.
- Various Python 3.5 issues fixed.
- std::array support added for Ruby and Python.
- shared_ptr support added for Ruby.
- Minor improvements for CFFI, Go, Java, Perl, Python, Ruby.

SWIG-3.0.7 summary:
- Add support for Octave-4.0.0.
- Remove potential Android security exploit in generated Java classes.
- Minor new features and bug fixes.

SWIG-3.0.6 summary:
- Stability and regression fixes.
- Fixed parsing of C++ corner cases.
- Language improvements and bug fixes for C#, Go, Java, Lua, Python, R.

SWIG-3.0.5 summary:
- Added support for Scilab.
- Important Python regression fix when wrapping C++ default arguments.
- Minor improvements for C#, Go, Octave, PHP and Python.

SWIG-3.0.4 summary:
- Python regression fix when wrapping C++ default arguments.
- Improved error messages.

SWIG-3.0.3 summary:
- Add support for C++11 strongly typed enumerations.
- Numerous bug fixes and minor enhancements for C#, D, Go, Java,
 Javascript, PHP, Perl and Python wrappers.

SWIG-3.0.2 summary:
- Bug fix during install and a couple of other minor changes.

SWIG-3.0.1 summary:
- Javascript module added. This supports JavascriptCore (Safari/Webkit),
 v8 (Chromium) and node.js currently.
- A few notable regressions introduced in 3.0.0 have been fixed - in
 Lua, nested classes and parsing of operator <<.
- The usual round of bug fixes and minor improvements for:
 C#, GCJ, Go, Java, Lua, PHP and Python.

SWIG-3.0.0 summary:
- This is a major new release focusing primarily on C++ improvements.
- C++11 support added. Please see documentation for details of supported
 features: https://www.swig.org/Doc3.0/CPlusPlus11.html
- Nested class support added. This has been taken full advantage of in
 Java and C#. Other languages can use the nested classes, but require
 further work for a more natural integration into the target language.
 We urge folk knowledgeable in the other target languages to step
 forward and help with this effort.
- Lua: improved metatables and support for %nspace.
- Go 1.3 support added.
- Python import improvements including relative imports.
- Python 3.3 support completed.
- Perl director support added.
- C# .NET 2 support is now the minimum. Generated using statements are
 replaced by fully qualified names.
- Bug fixes and improvements to the following languages:
 C#, Go, Guile, Java, Lua, Perl, PHP, Python, Octave, R, Ruby, Tcl
- Various other bug fixes and improvements affecting all languages.
- Note that this release contains some backwards incompatible changes
 in some languages.
- Full detailed release notes are in the changes file.

SWIG-2.0.12 summary:
- This is a maintenance release backporting some fixes from the pending
 3.0.0 release.
- Octave 3.8 support added.
- C++11 support for new versions of erase/insert in the STL containers.
- Compilation fixes on some systems for the generated Lua, PHP, Python
 and R wrappers.

SWIG-2.0.11 summary:
- Minor bug fixes and enhancements mostly in Python, but also
 C#, Lua, Ocaml, Octave, Perl, PHP, Python, R, Ruby, Tcl.

SWIG-2.0.10 summary:
- Ruby 1.9 support is now complete.
- Add support for Guile 2.0 and Guile 1.6 support (GH interface) has
 been dropped.
- Various small language neutral improvements and fixes.
- Various bug fixes and minor improvements specific to C#, CFFI, D,
 Java, Octave, PHP, Python,
- Minor bug fix in ccache-swig.
- Development has moved to Github with Travis continuous integration
 testing - patches using https://github.com/swig/swig are welcome.

SWIG-2.0.9 summary:
- Improved typemap matching.
- Ruby 1.9 support is much improved.
- Various bug fixes and minor improvements in C#, CFFI, Go, Java,
 Modula3, Octave, Perl, Python, R, Ruby, Tcl and in ccache-swig.

SWIG-2.0.8 summary:
- Fix a couple of regressions introduced in 2.0.5 and 2.0.7.
- Improved using declarations and using directives support.
- Minor fixes/enhancements for C#, Java, Octave, Perl and Python.

SWIG-2.0.7 summary:
- Important regression fixes since 2.0.5 for typemaps in general and
 in Python.
- Fixes and enhancements for Go, Java, Octave and PHP.

SWIG-2.0.6 summary:
- Regression fix for Python STL wrappers on some systems.

SWIG-2.0.5 summary:
- Official Android support added including documentation and examples.
- Improvements involving templates:
 1) Various fixes with templates and typedef types.
 2) Some template lookup problems fixed.
 3) Templated type fixes to use correct typemaps.
- Autodoc documentation generation improvements.
- Python STL container wrappers improvements including addition of
 stepped slicing.
- Approximately 70 fixes and minor enhancements for the following
 target languages: AllegroCL, C#, D, Go, Java, Lua, Ocaml, Octave,
 Perl, PHP, Python, R, Ruby, Tcl, Xml.

SWIG-2.0.4 summary:
- This is mainly a Python oriented release including support for Python
 built-in types for superior performance with the new -builtin option.
 The -builtin option is especially suitable for performance-critical
 libraries and applications that call wrapped methods repeatedly.
 See the python-specific chapter of the SWIG manual for more info.
- Python 3.2 support has also been added and various Python bugs have
 been fixed.
- Octave 3.4 support has also been added.
- There are also the usual minor generic improvements, as well as bug
 fixes and enhancements for D, Guile, Lua, Octave, Perl and Tcl.

SWIG-2.0.3 summary:
- A bug fix release including a couple of fixes for regressions in the
 2.0 series.

SWIG-2.0.2 summary:
- Support for the D language has been added.
- Various bug fixes and minor enhancements.
- Bug fixes particular to the Clisp, C#, Go, MzScheme, Ocaml, PHP, R,
 Ruby target languages.

SWIG-2.0.1 summary:
- Support for the Go language has been added.
- New regular expression (regex) encoder for renaming symbols based on
 the Perl Compatible Regular Expressions (PCRE) library.
- Numerous fixes in reporting file and line numbers in error and warning
 messages.
- Various bug fixes and improvements in the C#, Lua, Perl, PHP, Ruby
 and Python language modules.

SWIG-2.0.0 summary:
- License changes, see LICENSE file and https://www.swig.org/legal.html.
- Much better nested class/struct support.
- Much improved template partial specialization and explicit
 specialization handling.
- Namespace support improved with the 'nspace' feature where namespaces
 can be automatically translated into Java packages or C# namespaces.
- Improved typemap and symbol table debugging.
- Numerous subtle typemap matching rule changes when using the default
 (SWIGTYPE) type. These now work much like C++ class template partial
 specialization matching.
- Other small enhancements for typemaps. Typemap fragments are also now
 official and documented.
- Warning and error display refinements.
- Wrapping of shared_ptr is improved and documented now.
- Numerous C++ unary scope operator (::) fixes.
- Better support for boolean expressions.
- Various bug fixes and improvements in the Allegrocl, C#, Java, Lua,
 Octave, PHP, Python, R, Ruby and XML modules.

SWIG-1.3.40 summary:
- SWIG now supports directors for PHP.
- PHP support improved in general.
- Octave 3.2 support added.
- Various bug fixes/enhancements for Allegrocl, C#, Java, Octave, Perl,
 Python, Ruby and Tcl.
- Other generic fixes and minor new features.

SWIG-1.3.39 summary:
- Some new small feature enhancements.
- Improved C# std::vector wrappers.
- Bug fixes: mainly Python, but also Perl, MzScheme, CFFI, Allegrocl
 and Ruby

SWIG-1.3.38 summary:
- Output directory regression fix and other minor bug fixes

SWIG-1.3.37 summary:
- Python 3 support added
- SWIG now ships with a version of ccache that can be used with SWIG.
 This enables the files generated by SWIG to be cached so that repeated
 use of SWIG on unchanged input files speeds up builds quite considerably.
- PHP 4 support removed and PHP support improved in general
- Improved C# array support
- Numerous Allegro CL improvements
- Bug fixes/enhancements for Python, PHP, Java, C#, Chicken, Allegro CL,
 CFFI, Ruby, Tcl, Perl, R, Lua.
- Other minor generic bug fixes and enhancements

SWIG-1.3.36 summary:
- Enhancement to directors to wrap all protected members
- Optimisation feature for objects returned by value
- A few bugs fixes in the PHP, Java, Ruby, R, C#, Python, Lua and
 Perl modules
- Other minor generic bug fixes

SWIG-1.3.35 summary:
- Octave language module added
- Bug fixes in Python, Lua, Java, C#, Perl modules
- A few other generic bugs and runtime assertions fixed

SWIG-1.3.34 summary:
- shared_ptr support for Python
- Support for latest R - version 2.6
- Various minor improvements/bug fixes for R, Lua, Python, Java, C#
- A few other generic bug fixes, mainly for templates and using statements

SWIG-1.3.33 summary:
- Fix regression for Perl where C++ wrappers would not compile
- Fix regression parsing macros

SWIG-1.3.32 summary:
- shared_ptr support for Java and C#
- Enhanced STL support for Ruby
- Windows support for R
- Fixed long-standing memory leak in PHP Module
- Numerous fixes and minor enhancements for Allegrocl, C#, cffi, Chicken, Guile,
 Java, Lua, Ocaml, Perl, PHP, Python, Ruby, Tcl.
- Improved warning support

SWIG-1.3.31 summary:
- Python modern classes regression fix

SWIG-1.3.30 summary:
- Python-2.5 support
- New language module: R
- Director support added for C#
- Numerous director fixes and improvements
- Improved mingw/msys support
- Better constants support in Guile and chicken modules
- Support for generating PHP5 class wrappers
- Important Java premature garbage collection fix
- Minor improvements/fixes in cffi, php, allegrocl, perl, chicken, lua, ruby,
 ocaml, python, java, c# and guile language modules
- Many many other bug fixes

SWIG-1.3.29 summary:
- Numerous important bug fixes
- Few minor new features
- Some performance improvements in generated code for Python

SWIG-1.3.28 summary:
- More powerful renaming (%rename) capability.
- More user friendly warning handling.
- Add finer control for default constructors and destructors. We discourage
 the use of the 'nodefault' option, which disables both constructors and
 destructors, leading to possible memory leaks. Use instead 'nodefaultctor'
 and/or 'nodefaultdtor'.
- Automatic copy constructor wrapper generation via the 'copyctor' option/feature.
- Better handling of Windows extensions and types.
- Better runtime error reporting.
- Add the %catches directive to catch and dispatch exceptions.
- Add the %naturalvar directive for more 'natural' variable wrapping.
- Better default handling of std::string variables using the %naturalvar directive.
- Add the %allowexcept and %exceptionvar directives to handle exceptions when
 accessing a variable.
- Add the %delobject directive to mark methods that act like destructors.
- Add the -fastdispatch option to enable smaller and faster overload dispatch
 mechanism.
- Template support for %rename, %feature and %typemap improved.
- Add/doc more debug options, such as -dump_module, -debug_typemaps, etc.
- Unified typemap library (UTL) potentially providing core typemaps for all
 scripting languages based on the recently evolving Python typemaps.
- New language module: Common Lisp with CFFI.
- Python, Ruby, Perl and Tcl use the new UTL, many old reported and hidden
 errors with typemaps are now fixed.
- Initial Java support for languages using the UTL via GCJ, you can now use
 Java libraries in your favorite script language using gcj + swig.
- Tcl support for std::wstring.
- PHP4 module update, many error fixes and actively maintained again.
- Allegrocl support for C++, also enhanced C support.
- Ruby support for bang methods.
- Ruby support for user classes as native exceptions.
- Perl improved dispatching in overloaded functions via the new cast and rank
 mechanism.
- Perl improved backward compatibility, 5.004 and later tested and working.
- Python improved backward compatibility, 1.5.2 and later tested and working.
- Python can use the same cast/rank mechanism via the -castmode option.
- Python implicit conversion mechanism similar to C++, via the %implicitconv
 directive (replaces and improves the implicit.i library).
- Python threading support added.
- Python STL support improved, iterators are supported and STL containers can
 use now the native PyObject type.
- Python many performance options and improvements, try the -O option to test
 all of them. Python runtime benchmarks show up to 20 times better performance
 compared to 1.3.27 and older versions.
- Python support for 'multi-inheritance' on the python side.
- Python simplified proxy classes, now swig doesn't need to generate the
 additional 'ClassPtr' classes.
- Python extended support for smart pointers.
- Python better support for static member variables.
- Python backward compatibility improved, many projects that used to work
 only with  swig-1.3.21 to swig-1.3.24 are working again with swig-1.3.28
- Python test-suite is now 'valgrinded' before release, and swig also
 reports memory leaks due to missing destructors.
- Minor bug fixes and improvements to the Lua, Ruby, Java, C#, Python, Guile,
 Chicken, Tcl and Perl modules.

SWIG-1.3.27 summary:
- Fix bug in anonymous typedef structures which was leading to strange behaviour

SWIG-1.3.26 summary:
- New language modules: Lua, CLISP and Common Lisp with UFFI.
- Big overhaul to the PHP module.
- Change to the way 'extern' is handled.
- Minor bug fixes specific to  C#, Java, Modula3, Ocaml, Allegro CL,
 XML, Lisp s-expressions, Tcl, Ruby and Python modules.
- Other minor improvements and bug fixes.

SWIG-1.3.25 summary:
- Improved runtime type system.  Speed of module loading improved in
 modules with lots of types.  SWIG_RUNTIME_VERSION has been increased
 from 1 to 2, but the API is exactly the same; only internal changes
 were made.
- The languages that use the runtime type system now support external
 access to the runtime type system.
- Various improvements with typemaps and template handling.
- Fewer warnings in generated code.
- Improved colour documentation.
- Many C# module improvements (exception handling, prevention of early
 garbage collection, C# attributes support added, more flexible type
 marshalling/asymmetric types.)
- Minor improvements and bug fixes specific to the C#, Java, TCL, Guile,
 Chicken, MzScheme, Perl, Php, Python, Ruby and Ocaml modules).
- Various other bug fixes and memory leak fixes.

SWIG-1.3.24 summary:
- Improved enum handling
- More runtime library options
- More bugs fixes for templates and template default arguments, directors
 and other areas.
- Better smart pointer support, including data members, static members
 and %extend.

SWIG-1.3.23 summary:
- Improved support for callbacks
- Python docstring support and better error handling
- C++ default argument support for Java and C# added.
- Improved c++ default argument support for the scripting languages plus
 option to use original (compact) default arguments.
- %feature and %ignore/%rename bug fixes and mods - they might need default
 arguments specified to maintain compatible behaviour when using the new
 default arguments wrapping.
- Runtime library changes: Runtime code can now exist in more than one module
 and so need not be compiled into just one module
- Further improved support for templates and namespaces
- Overloaded templated function support added
- More powerful default typemaps (mixed default typemaps)
- Some important %extend and director code bug fixes
- Guile now defaults to using SCM API.  The old interface can be obtained by
 the -gh option.
- Various minor improvements and bug fixes for C#, Chicken, Guile, Java,
 MzScheme, Perl, Python and Ruby
- Improved dependencies generation for constructing Makefiles.

SWIG-1.3.22 summary:
- Improved exception handling and translation of C errors or C++
 exceptions into target language exceptions.
- Improved enum support, mapping to built-in Java 1.5 enums and C#
 enums or the typesafe enum pattern for these two languages.
- Python - much better STL support and support for std::wstring,
 wchar_t and FILE *.
- Initial support for Modula3 and Allegro CL.
- 64 bit TCL support.
- Java and C#'s proxy classes are now nearly 100% generated from
 typemaps and/or features for finer control on the generated code.
- SWIG runtime library support deprecation.
- Improved documentation. SWIG now additionally provides documentation
 in the form of a single HTML page as well as a pdf document.
- Enhanced C++ friend declaration support.
- Better support for reference counted classes.
- Various %fragment improvements.
- RPM fixes.
- Various minor improvements and bug fixes for C#, Chicken, Guile, Java,
 MzScheme, Perl, Php, Python, Ruby and XML.