dev-2026-04

New Language Features

• Fixed Capacity Dynamic Arrays, adds [dynamic; N]T

New Compiler Improvements

• Limit maximum exponent of integer literals to avoid unnecessary work
• Add -in-source-order option to odin doc to show docs in source order within each file
• Support clang-style +/- prefixes in target features
• Fix #6396: handle full-width bit_field literal masks
• Fix #6401: generic cycle deadlock in struct layout
• Add support for other Android architectures
• Fix #5602: "Internal Compiler Error: Type_Info for 'x' could not be found" for poly procs with named parameters
• Continuous Compiler Improvements
• Add initial LLVM 22 support on non-Windows platforms
• More accurate -march:native feature selection
• Allow pointers to types which have subtype fields at offset 0 to be assignable in proc parameters.
• offset_of(some_bit_field) now raises a proper error
• Add intrinsics.type_field_bit_offset(typeid, string) to get a compile-time bit_field field offset in bits
• Add intrinsics.type_field_bit_size(typeid, string) to get a compile-time bit_field field size in bits (the value after |)
• Fix #6407: Global unions do not get initialized correctly
• Fix >= comparison base:runtime dependencies for string and cstring types
• Fix GB_PANIC format string in lb_emit_conv invalid subtype cast
• Fix [^]u16 to cstring16 transmute condition in lb_emit_conv
• Remove Tilde backend
• Fix #6484: Two when blocks which evaluate to true in a foreign block misses following decls
• Fix declaration order bug #6506: False-positive where-clause failures in recursive polymorphic subtype cases
• Fix declaration order bugs #5572 and #5961: Incorrectly rejecting valid in-progress/forward union references

New Packages

• core:crypto/argon2id initial import
• vendor:windows/wasapi
• vendor:sdl3/mixer

Package Improvements

• Add more JS to examples/all
• Update Unicode database to newer version
• Fix modular exponentiation in core:math/big
• Fix assign_at documentation
• core:fmt now formats time.Duration with a space between duration and unit when using % v
• Correct SIMD shr example documention
• Fix sync.Auto_Reset_Event signal deadlock
• core:sys/darwin/Foundation: fix NSTimer binding
• Partial 1.619.x d3d12 bindings
• core:mem/virtual: Fix for virtual arena overcommit bug #5821
• core:crypto: Add ARM AES hardware acceleration
• core:crypto: Add ARM SHA256 hardware acceleration
• core:fmt: Improve core:container/small_array formatting
• vendor:stb/vorbis: Add WASM support
• core:encoding/cbor: Fix order-dependent partial unmarshals
• core:encoding/json: Fix user unmarshaler example
• Fix possible OOM in core:os.get_working_directory() on Linux
• Fix #6455: core:mem/virtual.map_file_from_path ignores flags
• Fix for corner case in the core:mem scratch allocator.
• Minor cleanup in base:runtime and core:mem
• Fix #6495: Handle starting separator during name comparison in core:os
• Improved delete_key documentation to mention it's safe to delete keys while iterating a map as long as no resizes take place
• Fix source size check in core:crypto/aes ECB encrypt/decrypt

Full Change Log

Full Changelog: dev-2026-03...dev-2026-04

dev-2026-03

BREAKING Changes

• core:os has been replaced with our newly improved and rewritten v2, previously available at core:os/os2. The old core:os implementation will remain available at core:os/old until sometime in Q3 of 2026.

  • Article on Moving Towards a New "core:os"

• core:sys/info previously retrieved all information before main was entered, using @(init), and exposed everything via globals. It now gathers more information on demand, and returns everything via accessors for a consistent API. Where practical - like cpu name + features - those values will be cached.

New Language Features

• for init; x in y {} style loops

New Compiler Improvements

• Stop silently ignoring unknown directives on an inline asm expression
• Do not allow duplicated #partial directives on switch statements
• Add broadcasting to strings (Fix #1837)
• Improve LLVM version picking
• Fix name canonicalization for typed ranges in bit_set
• Fix bit_set parapoly specialization
• Fix separating of diverging procedure types from block statements
• Update Type_Info_Bit_Set to always record underlying type. Add runtime.type_info_underlying
• Fix #6347
• Fix #6270

New Packages

• core:crypto/ecdsa: Add ECDSA support

Package Improvements

• [BREAKING] core:os/os2 -> core:os integration
• [BREAKING] core:sys/info: Change API from globals to calls. Do as little work in @(init) as practical.
• Allow test names to be specified as a command line option for tests executable
• vendor:x11/xlib: Fix signature of XChangeWindowAttributes
• vendor:directx/d3d12: Added IGraphicsCommandList7 and fix access violation errors
• Minimize some internal depencies in the core packages, e.g. don't import core:mem just for mem.Allocator_Error
• vendor:box2d: Fix and try Git LFS
• core:log: Add support for js/wasm
• core:container/xar: Fixes and improvements
• core:container/pool: Fix parapoly type inference around address sanitization when using multiple Pool types
• core:container/handle_map: Improvement
• demo.odin Fix cross_3d typo
• core:encoding/hex: Add uppercase encoding
• core:bytes: Update comment on compare; add additional caller location propagation
• core:math/big: Clean up
• core:os: Fix silent failure in os.replace_path_separators if the separator was multi-byte
• Add additional tests
• core:sys/es: Fix build errors
• core:unicode/utf8: Fix utf-8 validation
• Vendor Wycheproof cryptographic tests under tests/core/
• Propagate allocator errors from certain unicode functions
• Fix some tools and examples after core:os update and using-stmt feature
• Fix typo in atomic.odin documentation
• core:os: Remove process_close and add process_terminate
• core:time: Correct 12-hour clock string
• Update Unicode specification
• vendor:curl: Fix what argument for url_set
• Small optimization for dynamic arrays
• vendor:miniaudio: Upgrade to 0.11.24
• core:container/priority_queue: Add example and tests
• core:text/regex: Fix \b handling in iterator
• vendor:sdl3: Update to 3.4.2
• Add bindings to allow custom hardware cursors
• core:nbio: Fix op reuse
• core:strings: Fix substring not returning end of range
• core:sys/windows: Add more win32 API bindings
• core:sys/windows: Fix incorrect PVOID/VOID use in some signatures
• core:sys/windows: Tighten up MultiByteToWideChar usage in utf8_to_wstring_buf
• vendor:stb/vorbis: Remove unnecessary core:c/libc import
• vendor:wasm/WebGL: Add bindings, fix Tex*Image*D
• core:os: Return .Permission_Denied for .EACCES in Posix and Linux
• core:crypto/_blake2: Fix final blocks call with partial block
• Kill deprecated file tags and fix assignment of package docs

Full Change Log

Full Changelog: dev-2026-02...dev-2026-03

dev-2026-02

New Language Features

• #+feature using-stmt
  • using as a statement and procedure parameter modifier is now an opt-in feature on a per-file basis rather than on by default
  • using on struct fields still works
• struct #simple
  • force a struct to use simple comparison if all of the fields "nearly simply comparable"
  • This is a niche solution to a niche problem
  • "simply comparable" are types which can be compared with the equivalent of C's memcmp directly (e.g. integers, booleans, aggregates of them)
  • "nearly simply comparable" include the simply comparable types and floats, since floats have different rules for +0, -0, and NaN, and are NEARLY simply comparable if you don't care about those edge cases
  • This struct directive will force a struct to be "simply comparable" even if its fields would make it "nearly simply comparable"

New Compiler Improvements

• Link-Time Optimization Support
  • -lto:thin and -lto:thin-files
• #must_tail directive and preserve/none/preserve/most/preserve/all calling conventions
  • Enables the ability to state how optimize for tail calls
• -disable-unwind
• Improvements to the constant conversion checks
• intrinsics.count_leading_ones and intrinsics.count_trailing_ones
• Show -target flag usage example in help
• Numerous debug info fixes
• Static linking on non-Windows platforms
• Add warning for size_of(&x) as it will always be size_of(rawptr) and probably a typo
• -target:freestanding_amd64_mingw
  • Allowing for linking to MinGW on Windows but for freestanding purposes (not general)
• Fix string16 issues on Mac and Linux
• Fix in/not_in on constant bit_sets
• Allow #+vet tags always work in addition to command line flag
• General fixes to -vet
• Type assertions now use the same context.assertion_failure_proc as assert and panic where possible
• #+feature force-type-assert which overrides -no-type-assert on a per-file basis
• Fix numerous data races in the compiler frontend
• Fix numerous threading bugs in the compiler frontend

New Packages

• core:nbio
  • Non-Blocking IO
• core:container/handle_map
  • Utilizing core:container/xar for stable backing data

Package Improvements

• core:thread
  • Add init and fini callback procedures to thread pools
• core:crypto
  • Add initial support for short Weierstrass curves
  • General improvements and additions
• core:testing
  • Use Windows API for SIG handling on Windows
• core:image
  • Fix TGA header detections
  • .do_not_expand_grayscale for TGA
• core:os/core:os/os2
  • Fix lookup_env_buf
  • Fix truncate-clamp op order when determining to_read size
• core:encoding/base64
  • Add support URL variant
• core:encoding/entity
  • Update handling of 2-codepoint based entities
• core:encoding/xml
  • Correct how comment handling and entities
• core:strings
  • Add loc := #caller_location to allocating procedures that would benefit for it
• core:sys/windows
  • add a few procedure bindings
  • sync barriers
  • procedure-based "macros" for RawInput
• core:text/regex
  • Pass given allocator on in create_iterator
• vendor:x11/xlib
  • Binding fixes, correcting incorrect signatures
• vendor:directx
  • Improve string type uses in DirectX bindings
• vendor:compress/lz4
  • Fix linking on non-Windows platforms
• vendor:curl
  • Fix linking on all unix-like OSes
• vendor:sdl3
  • Add missing procedures GetGpueDeviceProperties
  • Fix signature of RenderTextureRotated
• vendor:sdl3/image
  • Update to 3.4.0
• Move vendor:libc to vendor:libc-shim
  • This is to clarify that it exists as a "shim" rather than a proper replacement
• Update Orca bindings
• General additions and improvements to core:sys/linux
• Bulk-write to a slice in xoshiro/pcg_random_generator_proc
• Fixes to darwin/Foundation bindings

Full Change Log

Full Changelog: dev-2026-01...dev-2026-02

dev-2026-01

New Language Features

New Compiler Improvements

• Undetected type declaration cycles work-around
• Fix misleading error messages for init, fini and test attributes
• Fix automatic objc_msgSend on static methods via selector expression not resolving aliased types
• Fix #packed #all_or_none
• Fix auto objc_msgSend incorrectly treating certain class methods as instance methods.
• Fix handling of #force_inline
• Fix literal endianness

New Packages

• core:container/xar, an Odin-native implementation of an Exponential Array

Package Improvements

• Fix duplicate jpeg.load on JS
• Added more NSApplication and NSWindow bindings
• Update kb_text_shape to v2.03
• Fix default temp allocator underflow bug
• SDL2: Use multi-pointer so you can pass array
• Fix function signature for memmove in vendor:libc
• Freebsd: Fixed 'write' syscall to cause 'ESPIPE' on the pipe fd
• Update Box2d to 3.1.1
• Fix core:debug/trace example
• Make linux.IO_Vec.base a multipointer
• Ensure libc is linked on Windows for vendor:compress/lz4
• Change Return Type of sdl2.GetWindowFlags from u32 to Existing WindowFlags bit_set
• Fix minor issues within curl bindings
• core:time/timezone added additional search paths to match musl
• More bindings for Darwin
• Add @builtin to missing builtin procedure group procs
• os/os2: fix stale errors on windows when reading from console
• os/os2: better fix for the stale errors
• Fix runtime.print_i64 using an OOB index when min(i64) is given.
• os/os2: use ReadFile for Console reads too, at least for now
• core:sys/linux Add timerfd syscall wrappers
• Fix nfds_t alias for Linux
• core:io/utils: fix buffer size in write_* procs
• core:net docs: recv of 0 bytes with no error is a graceful close
• core:math/rand small documentation fix
• Address issue identifying CDATA in XML file
• encoding/base32: Fix padding validation for malformed input
• Fix standard json parsing / unmarshalling issue for pure arrays
• Add user32 scroll bar related bindings, and FrameRect
• Add missing 'caller_location' to several procedures in 'slice' package
• Update letter.odin
• WebGL binding additions
• Add JSON5/SJSON Comments When Marshalling
• Fix Unicode Output When Marshalling JSON
• Allow Unmarshalling to rune
• Custom json (un)marshalling, similar to core:fmt's custom formatters
• Fix net.map_to_ip6 offset
• [vendor/sdl3] update to sdl 3.4.0

Other

• Fix NetBSD CI by @krnowak in #6080

Full Changelog: dev-2025-12a...dev-2026-01

dev-2025-12a

New Language Features

New Compiler Improvements

• Fix duplicate code emission in type assertions.

New Packages

Package Improvements

• core:os/os2: Fix #5873
• Replace cURL library for Windows with one built against msvcrt
• Update cURL bindings to 8.17

Full Changelog: dev-2025-12...dev-2025-12a

dev-2025-12

Breaking changes

• BREAKING: Use chacha8rand as the default RNG.

The old default generator is available under core:math/rand in rand_pcg.odin in case you require a seed to return the same sequence as before.

New Language Features

• Introduce #all_or_none for structs, which requires that struct literals have all or none of the fields set

New Compiler Improvements

• Use SIP hash as name canonicalization hash
• Moved checking of -vet-unused-procedures and -vet-packages flags to after all flags are parsed
• Fixes for 32 bit with regards to typeid
• Fix #5894
• Remove #no_copy
• Don't check proc signature similarity for imported Objective-C methods
• Ubuntu arm ci and posix fixes
• Fix allocation of anonymous globals
• Fix #5967: Incorrect stack overflow warning for by ref switches over unions
• Skip collision panic when package names aren't unique

New Packages

• Add vendor:curl

Package Improvements

• Improve docs for stable sort procedures
• Fix: linalg.quaternion_from_forward_and_up
• Clone unquoted strings in encoding/json
• Add missing SetLayeredWindowAttributes
• Add io uring API
• Add FreeLibraryAndExitThread in kernel32. Add EnumProcessModules in psapi
• Fix typo in NS.String_initWithCString
• Remove the Darwin-specific paths from thread_unix
• Fix thread_act_t size
• Fix: make choice_bit_set respect bit_set domain
• math/rand: Add range-based number generation procedures
• Fix is_pointer_internally not handling Named Types
• Faster big.itoa
• Add Xoshiro256 RNG
• Add LockFileEx/UnlockFileEx and related flags
• Fix vendor:stb/image resize alpha_channel parameter type to c.int
• Move some OS General_Error values to io.Error
• Fix out of bounds access when parsing end_pos
• Add WSASendTo and WSARecvFrom
• Update d3d12 bindings for D3D12_FEATURE_D3D12_TIGHT_ALIGNMENT
• Add NSWindow coordinate space conversion bindings
• Don't build log allocator file on freestanding targets
• Adjust docs links for satellite SDL libraries
• Increase base64 decoding table size to 256, preventing out of bounds reads
• vendor/xlib: a few more IM-related procedures and constants
• add math.sign and math.sign_bit overloads for int types
• Implement more Linux syscalls
• Add SIO_UDP_CONNRESET winsock constant
• os2.File_Stream

Other

• Fix up macOS CI

Full Changelog: dev-2025-11...dev-2025-12

dev-2025-11

Licensing Changes

• Change Odin's LICENSE to zlib from BSD 3-clause

New Language Features

• intrinsics.concatenate
  • Concatentation of constant slices, strings, and some arrays at compile time
• intrinsics.objc_super & @(objc_superclass=<type>)

New Compiler Improvements

• Objective-C interface improvements
  • intrinsics.objc_super and automatically emit objc_msgSend calls where necessary for @(objc_superclass) attribute
  • Fix block symbols naming conflict across modules
• LLVM backend fixes
  • #simd vector only uses bit cast when elements are not pointers
  • Fix bitcasting context pointer to prevent compilation errors on LLVM-14
  • Numerous constant union improvements
  • Prefer the Type * ver LLVMTypeRef when looking up struct_field_remapping due to lack of uniqueness
• Default parameter exclusion counting improvement for procedure groups
• Improved -target-features flag by allow the user to disable a target feature
  • -target-features:-sse,-sse2,-avx
• -export-linked-libs-file:<string> flag to export the linked libraries to a file
• Fix a few compiler hangs on macOS.
• LLVM 21 support for non-Windows platforms
• Fix: #load alignment bug
  • set minimum alignment to 16-bytes
• Fix orca linking path
• Add #subtype/using to name canonicalization rules
• Numerous frontend bugs fixed

New Packages

Package Improvements

• More documentation improvements across the core library
• General improvements and more documentation for core:os/os2
• Add inject_at_soa and append_nothing_soa
• vendor:wgpu update to 27.0.2.0
• core:unicode/utf8: Add Grapheme_Iterator
• New slice.sort implementation to allow for better code generation and general API
• Deprecate the C style procedures in strconv (e.g. iota, atoi, etc`)
• WASM: Fix odin.js undefined this.mem
• Fix sRGB <-> linear RGB conversion
• core:encoding/json fixes
  • Fix null parsing in certain cases
• core:encoding/cbor: Fix epoch tag with small values
• core:container/rbtree add find_or_insert
• Fix bindings generator for vendor:vulkan for extensions and ~0 style constants
• Disable bounds checking where appropriate for Unicode and UTF-8 procedures
• vendor:fontstash: Fix crash with .TTC files
• core:simd : Fix incorrectly named calls in bit_not
• vendor:sdl3: Add PointInRectFloat
• vendor/egl
  • add a few more procedures and constants
  • Fix GetPlatformDisplay and CreatePlatformWindowSurface to use int instead of i32
• vendor:box2d
  • fixes to bindings mismatches
  • Add targetAngle to RevoluteJoint struct/procs
• core:odin/parser
  • fixes for end_pos
  • parse empty identifiers after selector as a selector expression with an empty field
• core:hash: add CCITT CRC-16
• Make packed conditional on EPoll_Event to match kernel
• core:math/linalg/hlsl: support half types
• core:math/ease: Add inverse ease procedures
• vendor:raylib: add MAX_MATERIAL_MAPS constant
• core:sys/darwin/Foundation: add additional AppKit bindings
• core:text/scanner allow for octal prefix style parsing for C-style ints

Full Changelog: dev-2025-10...dev-2025-11

dev-2025-10

New Language Features

New Compiler Improvements

• Improve type inferencing of literals when calling proc groups
• Windows i386 support
• Fix Darwin addObserver methods and add support for new Objc_Block
• Fix segfault involving string_to_string16 on Linux
• Improve OSX threading performance
• Basic support for constant union literals
• Add -build-diagnostics
• Prevent returning a struct containing compound literal slice
• Relax signature_parameter_similar_enough on struct params and fix various foreign signatures
• Preempt field checking on signature_parameter_similar_enough with a type ptr equality check
• Remove stray debug printf

New Packages

• [core/image]: Add baseline JPEG support

Package Improvements

• Use .Image_Dimensions_Too_Large in core:image
• tick_now: Use f64 (was f32) as a return type of odin_env.tick_now()
• Allow missing trailing comma with proc groups in core:odin parser
• Fix incorrect json encoding for control characters < 32
• Initializing big.Int constants is now "contextless"
• Add CancelIoEx and other overlapped I/O functions.
• Add missing caller location param to append in strings.Builder
• Add "contextless" to small_array get_safe and get_ptr_safe
• Zero small_array resize
• Unify filepath.join return between Unix/Windows
• Fix out-of-band allocations in dynamic arenas by
• Fix for temp_file name prefix being deallocated before being used
• Add runtime.conditional_mem_zero to improve heap_allocator performance on non-Windows systems
• Add digit_to_int to core:strconv
• Remove inaccurate tprint comment

Full Changelog: dev-2025-09...dev-2025-10

dev-2025-09

New Language Features

• Native support for UTF-16 strings: string16 and cstring16
  • Mostly for interfacing with Windows code, and other foreign code
• Define Integer Division By Zero #5556

New Compiler Improvements

• @(init) and @(fini) must be proc "contextless" ()
• Implement intrinsics.objc_block @harold-b in #5547
  • Implements the Apple block ABI.2010.3.16 natively
• Improve deference missing suggestion message
• Do not check for explicit allocators when determining proc in proc group by @janga-perlind in #5564
• Skip errors on polymorphic procs when in a proc group with other options
• Fix compiler segfault when trying to use proc at type level or trying to use () as a type

New Packages

Package Improvements

• Fixes to vendor:darwin/Metal
• Numerous minor fixes to base:runtime
• Improvements to base:runtime docs
• Fixes to vendor:wasm/WebGL bindings
• Cleanup in math/rand and runtime/random_generator
• Add missing xlib functions for getting and setting text properties
• vendor:OpenGL fix misnamed parameter by
• Make D3D12_FEATURE_DATA_D3D12_OPTIONS.MinPrecisionSupport a bitset
• Fix buddy allocator assert
• Check for EOF when scanning file tags
• Fix stride in memory_equal/compare_zero giving false positves
• Split SDL_ttf bindings to group with and without require_results
• Propogate #caller_location to core:container/queue procs
• Support using allocator resize in _reserve_soa
• Zero existing memory when using resize_soa
• Add add/remove_document_event_listener() to core:sys/wasm/js
• Fixed and added obj-c methods for NSWindow
• fix typo in CLSIDFromProgIDEx signature
• Fix broken wglUseFontBitmaps binding
• Add LPFN_GETACCEPTEXSOCKADDRS to ws2_32.odin
• Specify %m and %M as verbs for integer formatting in core:fmt
• Add @(require_results) attribute to procs returning an allocator
• Handle allocator error when appending in read_entire_file_from_file
• vendor:box2d fix CreateMotorJoint procedure signature
• Add build tags to posix/spawn.odin

Full Changelog: dev-2025-08...dev-2025-09

dev-2025-08

New Language Features

New Compiler Improvements

• General compiler bug fixes
• intrinsics.type_enum_is_contiguous
• intrinsics.simd_runtime_swizzle
• Add iOS and iPhoneSimulator subtargets for -target:darwin
• Fix @(objc_implement) methods not respecting @(objc_is_class_method)
• @(objc_name) attribute be inferrable
• Add Did you mean? for card/len
• #+vet explicit-allocators
• Saner stack linker flags for WASM
• Fix macos amd64 builds
• amd64 ABI fixes regarding certain types of SIMD vectors

New Packages

Package Improvements

• Update core:prof/spall to version 3
  • Adds @(no_instrumentation) to spall buffer and SCOPED operations
• core:hash/xxhash: Static SIMD Support for XXH3
• Minor fixes to core:mem/virtual edge cases
• Unix build script for kb_text_shape
• Add IUnknown UUID for win32 related code
• crypto/hash: hash_bytes_to_buffer slice result to digest size
• Minor fix to -default-to-nil-allocator
• Disable filepath/match.odin and filepath/walk.odin compilation on js targets
• Minor fixes to SDL_image save procedure that should return a boolean
• Mach Process Control
• Fix amd64 no-crt entry assembly
• Add cgltf filter type and wrap mode enums
• SDL2 - AudioAllowChangeFlags bit_set
• core:thread - set stack size to rlimit for *nix platforms

Full Changelog: dev-2025-07...dev-2025-08