Version history#

Koffi 2.9#

Koffi 2.9.0-beta.2 (2024-07-12)#

  • Add support for char32_t and wchar_t (wide) strings

  • Include Linux/musl x64 prebuild (based on Alpine)

Koffi 2.8#

Koffi 2.8.11 (2024-06-19)#

  • Work around MSVC compiler bug introduced in Visual Studio 17.10


Use on platforms without pre-built binaries is broken in Koffi 2.8.10, skip this version.

Koffi 2.8.9 (2024-05-17)#

  • Fix ABI issue regarding bool return values on x86_64 (and possibly other platforms)

Koffi 2.8.8 (2024-04-26)#

  • Support use of buffers with mismatched size (truncation or zero-filling)

Koffi 2.8.7 (2024-04-23)#

Koffi 2.8.6 (2024-04-12)#

Koffi 2.8.5 (2024-04-11)#

  • Prevent obviously invalid type and member names

  • Fix possible infinite loop / UB for koffi.load() errors on POSIX systems

  • Fix null return value instead of exception for some errors in koffi.load() on Windows

Koffi 2.8.4 (2024-04-09)#

  • Use simpler workaround for Node 20.12+ and 21.6+ to avoid excessive memory use


Some pre-built binaries are missing in Koffi 2.8.3, skip this version.

Koffi 2.8.2 (2024-04-07)#

Koffi 2.8.1 (2024-04-04)#

  • Fix incompatibility with Node 20.12+ and 21.6+

Koffi 2.8.0 (2024-02-12)#

  • Support pushing pointers for string arguments

  • Add koffi.alloc() for stable pointers

Koffi 2.7#

Koffi 2.7.4 (2024-02-04)#

  • Support callbacks happening on main thread but outside JS call (such as during event loop)

  • Improve stability after koffi.reset()

  • Expose internal Node/NAPI env pointer

  • Name main Koffi API functions

Koffi 2.7.3 (2024-01-26)#

  • Support decoding NULL terminated arrays

Koffi 2.7.2 (2024-01-15)#

  • Add missing TypeScript declaration for

  • Fix TypeScript declaration of koffi.encode()

  • Try to improve compatibility with webpack

Koffi 2.7.1 (2024-01-02)#

  • Support C-like int[3] syntax for fixed array types

  • Refuse type specifiers with invalid tokens at the end (previously ignored)

Koffi 2.7.0 (2023-12-21)#

Koffi 2.6#

Koffi 2.6.12 (2023-12-11)#

  • Fix possible crash introduced in Koffi 2.6.11

Koffi 2.6.11 (2023-12-05)#

  • Speed up resolving simple and often used type names

  • Fix use of optional length argument with koffi.encode()

Koffi 2.6.10 (2023-11-29)#

  • Protect GetLastError() value from Node.js and V8 on Windows

Koffi 2.6.9 (2023-11-25)#

  • Search in DLL directory for additional dependencies on Windows

  • Ignore prototype properties when making structs or unions

  • Show detected version of Node when not adequate

  • Minor documentation fixes


Loading Win32 system libraries can fail in Koffi 2.6.8, skip this version.

Koffi 2.6.6 (2023-10-28)#

  • Better handle errors while making struct or union types

Koffi 2.6.5 (2023-10-28)#

  • Allow self-referential structs and unions

  • Fix rare Node.js “FATAL ERROR” with some invalid type specifiers

Koffi 2.6.4 (2023-10-26)#

  • Fix build issue with recent Visual Studio versions

Koffi 2.6.3 (2023-10-17)#

  • Add indirect loading script to help some bundlers


Pre-built binaries don’t work correctly in Koffi 2.6.2, skip this version.

Koffi 2.6.1 (2023-09-18)#

  • Support string direction qualifiers in classic function definitions

  • Fix possible off-by-one array access when parsing type name

Koffi 2.6.0 (2023-09-13)#

New features:

  • Use koffi.symbol() to make pointers to exported variables (or other symbols)

  • Use koffi.encode() to explictly encode data from JS to C memory

  • Use shared library lazy-loading (RTLD_LAZY) on POSIX platforms

Other changes:

  • Print more helpful error for Win32/Win64 DLL mismatches

  • Add missing ‘Union’ primitive value in TS definition file

Koffi 2.5#

Koffi 2.5.20 (2023-08-31)#

  • Fix possible crash with async registered callbacks introduced in Koffi 2.5.19

  • Various documentation fixes and improvements

Koffi 2.5.19 (2023-08-29)#

  • Create thread-safe function broker lazily

  • Add koffi.reset() for type names and async broker

Koffi 2.5.18 (2023-08-27)#

  • Fix compatibility with Electron

Koffi 2.5.16 (2023-08-25)#

  • Run Koffi tests through usual index.js entry point

  • Fix DLL error when using Koffi from NW.js on Windows

  • Simplify NW.js Koffi example


Pre-built binaries don’t work correctly in Koffi 2.5.13 to 2.5.15, skip those versions.

Koffi 2.5.12 (2023-08-21)#

  • Fix native module bundling for FreeBSD ARM64 and Linux RISC-V 64

  • Increase maximum number of parameters to 64

Koffi 2.5.11 (2023-08-03)#

  • Support casting function pointers with

  • Build in C++20 mode

Koffi 2.5.10 (2023-08-01)#

  • Fix CMake regression when client has to build Koffi

Koffi 2.5.9 (2023-07-28)#

Main changes:

  • Use bundler-friendly static require calls in Koffi

  • Add packaging examples to documentation

Other changes:

  • Add missing unload() export to TS file

  • Add export for koffi.types in TS file

Koffi 2.5.8 (2023-07-26)#

  • Add more search paths for native Koffi modules

  • Add section about bundling to documentation

Koffi 2.5.7 (2023-07-19)#

  • Point package to new repository

Koffi 2.5.6 (2023-07-19)#

  • Increase limit of output parameters from 16 to 32

Koffi 2.5.5 (2023-07-17)#

  • Support decoding non-char null-terminated arrays

Koffi 2.5.4 (2023-07-14)#

  • Fix koffi.pointer() not accepting disposable types

  • Fix potential issues when making pointers to anonymous types

Koffi 2.5.3 (2023-07-05)#

  • Add missing union exports in TS definition file

  • Fix some parameter names in TS definition file

Koffi 2.5.2 (2023-07-04)#

  • Default initialize unset object/struct members

Koffi 2.5.1 (2023-06-20)#

  • Fix crash with some struct types in System V 64 ABI

  • Always use direct passthrough for buffer arguments

Koffi 2.5.0 (2023-06-20)#

New features:

Other fixes:

  • Fix ABI for single-float aggregate return on i386 BSD systems

  • Don’t mess with Node.js signal handling on POSIX systems

Koffi 2.4#

Koffi 2.4.2 (2023-06-04)#

  • Support calling variadic function pointers

  • Add documentation for function pointers

Koffi 2.4.1 (2023-06-03)#

Main changes:

Other changes:

  • Increase maximum number of callbacks to 8192

  • Build Koffi with static CRT on Windows

  • Reorganize Koffi data conversion documentation

  • Add deprecated koffi.handle to TS file

Koffi 2.3#

Koffi 2.3.20 (2023-05-15)#

  • Support explicit library unloading with lib.unload()

Koffi 2.3.19 (2023-04-21)#

  • Actually allow non-ambiguous [string] values for void * arguments

Koffi 2.3.18 (2023-04-21)#

  • Fix possible crash on exit caused by unregistered callbacks

Koffi 2.3.17 (2023-04-20)#

  • Allow strings for input void *, int8_t * and int16_t * pointer arguments

  • Support using [string] (single-element string arrays) for polymorphic input/output arguments

Koffi 2.3.16 (2023-04-11)#

  • Fix Windows ARM64 build to work with official Node.js version

  • Compile Windows builds with Visual Studio 2022 17.5.3

  • Support null in and koffi.address()

Koffi 2.3.15 (2023-04-10)#

  • Improve manual decoding of 0-terminated strings

  • Add checks around array conversion hints

Koffi 2.3.14 (2023-04-05)#

  • Add koffi.errno() function to get and set current errno value

  • Add koffi.os.errno object with valid errno codes

Koffi 2.3.13 (2023-03-30)#

  • Add koffi.address() to get the raw value of a wrapper pointer

Koffi 2.3.12 (2023-03-30)#

  • Fix broken syntax in TS definition file

  • Add missing exported properties in TS file

Koffi 2.3.11 (2023-03-30)#

Main changes:

  • Allow numbers and BigInts to be used for pointer arguments

Other changes:

  • Use SQLITE_TRANSIENT in SQLite test code

  • Avoid using statx() to allow compilation with glibc < 2.28

  • Reorganize NPM package files to be less convoluted

Koffi 2.3.9 (2023-03-10)#

  • Relicense under MIT license

Koffi 2.3.8 (2023-02-28)#

  • Disable non-ready union support

  • Simplify Windows stack allocation and drop NOACCESS and GUARD pages

  • Adjust Windows TEB SEH chain and GuaranteedStackBytes for Koffi calls

Koffi 2.3.7 (2023-02-27)#

  • Fix missing require in index.js (@gastonFrecceroNapse)

  • Reduce NPM package bloat (from 65 MB to 20 MB) caused by changes in 2.3.6

Koffi 2.3.6 (2023-02-26)#

  • Fix broken TS definition file

  • Keep all prebuilt binaries and load correct one at runtime

Koffi 2.3.5 (2023-02-24)#

Main fixes:

  • Fix rare random crashes with async callbacks

  • Fix some bugs with RISC-V 64 ABI

Other changes:

  • Expose array type hint in koffi.introspect()

  • Add missing koffi.array() export in TS definition

  • Make KoffiFunction more flexible in TS definition (@insraq)

  • Add a KoffiFunc helper type in TS typing (@insraq)

  • Mark optional properties in TS TypeInfo class

  • Minor performance improvements

Koffi 2.3.4 (2023-01-31)#

  • Fix error when installing Koffi on Windows (2.3.2)

Koffi 2.3.2 (2023-01-30)#

Main changes:

Other changes:

  • Avoid CNoke dependency

  • Clear out development dependencies from package.json

Koffi 2.3.1 (2023-01-30)#

  • Error out when trying to use ambiguous void * arguments (input and/or output)

  • Adjust TypeScript definitions (@insraq)

  • Fix possible crash when parsing invalid prototype

Koffi 2.3.0 (2023-01-25)#

Main changes:

Other changes:

  • Drop TypedArray type check for array and pointer values (only the size matters)

  • Allow ArrayBuffer everywhere TypedArray is supported

  • Add TypeScript definition for Koffi (@insraq)

  • Improve documentation about opaque and polymorphic structs

  • Improve documentation for koffi.decode()

  • Reduce NPM package size (from 100 MB to 25 MB) by removing test code and dependencies

Koffi 2.2#

Koffi 2.2.5 (2023-01-23)#

  • Relicense Koffi under LGPL 3.0

Koffi 2.2.4 (2023-01-19)#

  • Fix memory leak on Windows (in Koffi 2.2.3) when running many async calls

  • Reorganize documentation pages

Koffi 2.2.3 (2023-01-17)#

Koffi 2.2.2 (2023-01-14)#

Main fixes:

  • Support transparent asynchronous callbacks

  • Expand from a maximum of 16+16 to 1024 callbacks running in parallel

Other fixes:

  • Fix bundler support by removing shebang from index.js

  • Fix bugs when loading Koffi multiples times in same process (context aware module)

  • Check N-API version when module is loaded

  • Optimize callback unregistration

Koffi 2.2.1 (2022-12-21)#

Koffi 2.2.0 (2022-12-20)#

New features:

Other fixes:

  • Correctly validate output parameter types

  • Fix assertion with void * parameters

Koffi 2.1#

Koffi 2.1.5 (2022-11-27)#

  • Add missing file to NPM package

Koffi 2.1.4 (2022-11-25)#

Main changes:

  • Increase maximum type size from 32 kiB to 64 MiB

  • Add configurable option for maximum type size

Other changes:

Koffi 2.1.3 (2022-10-31)#

  • Support up to 16 output parameters (instead of 8)

Koffi 2.1.2 (2022-10-31)#

  • Support up to 8 output parameters (instead of 4)

Koffi 2.1.1 (2022-08-16)#

  • Fix potential memory allocation bugs

Koffi 2.1.0 (2022-08-13)#

Main changes:

  • Add to support polymorphic APIs based on void * parameters

  • Add endian-sensitive integer types: intX_le_t, intX_be_t, uintX_le_t, uintX_be_t

  • Accept typed arrays for void * parameters

  • Introduce koffi.opaque() to replace koffi.handle() (which remains supported until Koffi 3.0)

  • Support JS Array and TypedArray to fill struct and array pointer members

Other changes:

  • Improve global performance with inlining and unity builds

  • Add size_t primitive type

  • Support member-specific alignement values in structs

  • Detect impossible parameter and return types (such as non-pointer opaque types)

  • Various documentation fixes and improvements

Koffi 2.0#

Koffi 2.0.1 (2022-07-30)#

  • Return undefined (instead of null) for void functions

Koffi 2.0.0 (2022-07-29)#

Major new features:

  • Add disposable types for automatic disposal of C values (such as heap-allocated strings)

  • Add support for registered callbacks, that can be called after the initial FFI call

  • Support named pointer types

  • Support complex type specifications outside of prototype parser

Minor new features:

  • Support type aliases with koffi.alias()

  • Add koffi.resolve() to resolve type strings

  • Expose all primitive type aliases in koffi.types

  • Correctly pass exceptions thrown in JS callbacks

Breaking API changes:

  • Change handling of callback types, which must be used through pointers

  • Change handling of opaque handles, which must be used through pointers

  • Support all types in koffi.introspect(type)

Consult the migration guide for more information.

Koffi 1.3#

Koffi 1.3.12 (2022-07-27)#

  • Fix support for Yarn package manager

Koffi 1.3.11 (2022-07-26)#

  • Fix broken parsing of void * when used for first parameter

Koffi 1.3.10 (2022-07-25)#

Main fixes:

  • Fix support for callbacks with more than 4 parameters on Windows x64

  • Fix support for callbacks with multiple floating-point arguments on ARM32 platforms

  • Fix possibly incorrect conversion for uint32_t callback parameters

Other changes:

  • Various documentation fixes and improvements

Koffi 1.3.9 (2022-07-15)#

  • Fix prebuild compatibility with Electron on Windows x64

Koffi 1.3.8 (2022-07-12)#

Main changes:

  • Prevent callback reuse beyond FFI call

  • Add BTI support for AAarch64 platforms (except Windows)

Other changes:

  • Fix and harmonize a few error messages

Koffi 1.3.7 (2022-07-07)#

Main fixes:

  • Fix crash when using callbacks inside structs

  • Support for null strings in record members

Other changes:

  • Add intptr_t and uintptr_t primitive types

  • Add str/str16 type aliases for string/string16

  • Various documentation fixes and improvements

Koffi 1.3.6 (2022-07-01)#

Main fixes:

  • Fix install error with Node < 15 on Windows (build system bug)

Other changes:

  • Detect incompatible Node.js versions when installing Koffi

  • Prebuild with Clang for Windows x64 and Linux x64 binaries

  • Various documentation improvements

Koffi 1.3.5 (2022-06-25)#

Main changes:

  • Fix memory leak when many async calls are running

  • Add configurable limit for maximum number of async calls (max_async_calls)

Other changes:

  • Reduce default async memory stack and heap size

  • Various documentation improvements

Koffi 1.3.4 (2022-06-24)#

  • Fix possible OpenBSD i386 crash with (void) functions

Koffi 1.3.3 (2022-06-24)#

Main fixes:

  • Fix misconversion of signed integer return value as unsigned

Other changes:

  • Support (void) (empty) function signatures

  • Disable unsafe compiler optimizations

  • Various documentation improvements

Koffi 1.3.2 (2022-06-23)#

  • Support compilation in C++14 mode (graceful degradation)

  • Support older toolchains on Linux (tested on Debian 9)

Koffi 1.3.1 (2022-06-22)#

  • The prebuilt binary is tested when Koffi is installed, and a rebuild happens if it fails to load

Koffi 1.3.0 (2022-06-22)#

Major changes:

  • Expand and move documentation to

  • Support JS arrays and TypedArrays for pointer arguments (input, output and mixed)

Other changes:

  • Convert NULL string pointers to null instead of crashing (return values, struct and array members, callbacks)

  • Default to ‘string’ array hint for char, char16 and char16_t arrays

  • Fix definition of long types on Windows x64 (LLP64 model)

  • Restrict automatic string conversion to signed char types

  • Detect floating-point ABI before using prebuilt binaries (ARM32, RISC-V)

  • Forbid duplicate member names in struct types

Koffi 1.2#

Koffi 1.2.4 (2022-06-12)#

  • Windows ARM64 is now supported

Koffi 1.2.3 (2022-06-11)#

  • A prebuilt binary for macOS ARM64 (M1) is now included

Koffi 1.2.1 (2022-06-11)#

This entry documents changes since version 1.1.0.

New features:

  • JS functions can be used as C callbacks (cdecl, stdcall) on all platforms

  • RISC-V 64 LP64D ABI is supported (LP64 is untested)

  • Expose settings for memory usage of synchronous and asynchronous calls

  • Transparent conversion between C buffers and strings

  • Tentative support for Windows ARM64 (untested)

Main fixes:

  • Fix excessive stack alignment of structs on x86 platforms

  • Fix potential problems with big int64_t/uint64_t values

  • Fix possible struct layout errors in push/pop code

  • Fix alignment issues in ARM32 push code

  • Fix incomplete/buggy support for HFA structs on ARM32 and ARM64

  • Fix crashes on OpenBSD caused by missing MAP_STACK flag

  • Fix non-sense “duplicate array type” errors

  • Fix value koffi.internal to false in module (normal) builds

  • Make sure we have a redzone below the stack for all architectures

  • Use slower allocation for big objects instead of failing

Todo list#

The following features and improvements are planned, not necessarily in that order:

  • Optimize passing of structs and arrays (with auto-generated JS)

  • Automate Windows/AArch64 (qemu) and macOS/AArch64 (how? … thanks Apple) tests

  • Create a real-world example, using several libraries (Raylib, SQLite, libsodium) to illustrate various C API styles

  • Add simple struct type parser

  • Port Koffi to PowerPC (POWER9+) ABI

  • Fix assembly unwind and CFI directives for better debugging experience