429c28c783
The write_vtable() function's comment claimed to "fill the WIP vtable with zeros" but make_space() only reserves memory without initializing it. When using custom allocators with non-zeroed buffers, unset vtable field entries would contain garbage instead of zero (which indicates "use default value"). This fix explicitly zeros the vtable memory after reserving space, matching the C++ implementation's buf_.fill_big() behavior. Added regression test using a garbage-filled allocator (0xAA) that verifies vtable entries for unset fields are properly zeroed. Fixes #8894
FlatBuffers
FlatBuffers is a cross platform serialization library architected for maximum memory efficiency. It allows you to directly access serialized data without parsing/unpacking it first, while still having great forwards/backwards compatibility.
Quick Start
-
Build the compiler for flatbuffers (
flatc)Use
cmaketo create the build files for your platform and then perform the compilation (Linux example).cmake -G "Unix Makefiles" make -j -
Define your flatbuffer schema (
.fbs)Write the schema to define the data you want to serialize. See monster.fbs for an example.
-
Generate code for your language(s)
Use the
flatccompiler to take your schema and generate language-specific code:./flatc --cpp --rust monster.fbsWhich generates
monster_generated.handmonster_generated.rsfiles. -
Serialize data
Use the generated code, as well as the
FlatBufferBuilderto construct your serialized buffer. (C++example) -
Transmit/store/save Buffer
Use your serialized buffer however you want. Send it to someone, save it for later, etc...
-
Read the data
Use the generated accessors to read the data from the serialized buffer.
It doesn't need to be the same language/schema version, FlatBuffers ensures the data is readable across languages and schema versions. See the
Rustexample reading the data written byC++.
Documentation
Go to our landing page to browse our documentation.
Supported operating systems
- Windows
- macOS
- Linux
- Android
- And any others with a recent C++ compiler (C++ 11 and newer)
Supported programming languages
Code generation and runtime libraries for many popular languages.
- C
- C++ - snapcraft.io
- C# - nuget.org
- Dart - pub.dev
- Go - go.dev
- Java - Maven
- JavaScript - NPM
- Kotlin
- Lobster
- Lua
- PHP
- Python - PyPI
- Rust - crates.io
- Swift - swiftpackageindex
- TypeScript - NPM
- Nim
Versioning
FlatBuffers does not follow traditional SemVer versioning (see rationale) but rather uses a format of the date of the release.
Contribution
- FlatBuffers Issues Tracker to submit an issue.
- stackoverflow.com with
flatbufferstag for any questions regarding FlatBuffers.
To contribute to this project, see CONTRIBUTING.
Community
Security
Please see our Security Policy for reporting vulnerabilities.
Licensing
Flatbuffers is licensed under the Apache License, Version 2.0. See LICENSE for the full license text.