flatbuffers/docs/source/flatc.md

FlatBuffers Compiler (flatc)

The main compiler for FlatBuffers is called flatc and is used to convert schema definitions into generated code files for a variety of languages.

After building flatc, it is used as follows:

flatc [ GENERATOR_OPTIONS ] [ -o PATH ] [- I PATH ] 
  FILES... 
  [ -- BINARY_FILES... ]

• The GENERATOR_OPTIONS specify the language(s) to compile code for as well as various features to enable/disable.

• The -o PATH specifies the path where the generated files are placed. It defaults to the current path if not specified.

• The -I PATH specifies the paths where included schema files are located. It defaults to the current path if not specified.

Input Files

FILES... specifies one or more schema or data files to process. They are processed in the order provided.

Schema Files

For schema files, language specifiers indicate what languages to generate code for.

• --cpp: C++
• --java: Java
• --kotlin: Kotlin
• --csharp: C#
• --go: Golang
• --python: Python
• --js: JavaScript
• --ts: TypeScript
• --php: PHP
• --dart: Dart
• --lua: Lua
• --lobster: Lobster
• --rust: Rust
• --swift: Swift
• --nim: Nim

Additionally, adding:

• --grpc Will generate RPC stub code for gRPC (not available in all languages)

Data Files

If FILES... contain data files, they can be exported to either a binary or JSON representation.

• --binary, -b: Generate a binary file containing a serialized flatbuffer.
• --json, -j: Generate JSON file from a serialized flatbuffer.

Both options require the corresponding schema file to be included first in the list of FILES....

=== "To Binary"

To serialize the JSON data in `mydata.json` using the schema `myschema.fbs`:

```sh
flatc --binary myschema.fbs mydata.json
```

This will generate a `mydata_wire.bin` file containing the serialized 
flatbuffer data.

=== "To JSON"

To convert the serialized binary flatbuffer `mydata.bin` using the schema 
`myschema.fbs` to JSON:

```sh
flatc --json myschema.fbs mydata.bin
```

This will generate a `mydata.json` file.