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 (in progress)
===========================

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
	    #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 - remove incorrect
            space in the function name, for example, operator= = is now operator==.