.TH FLATC "1" "October 2022" "" "User Commands"

.SH NAME

.B flatc

\(en FlatBuffers compiler

.SH SYNOPSIS

.B flatc

.RI [ OPTION ]...\:

.IR FILE ...\:

.RI [\-\-\  BINARY_FILE ...]

.SH OPTIONS

.IR FILE s

may be schemas (must end in

.BR .fbs ),

binary schemas (must end in

.BR .bfbs ),

or JSON files (conforming to preceding schema).

.IR BINARY_FILE s

after the

.B \-\-

must be binary flatbuffer format files.

.P

Output files are named using the base file name of the input,

and written to the current directory or the path given by

.BR \-o .

.TP

.B \-\-binary\fR, \fB\-b

Generate wire format binaries for any data definitions.

.TP

.B \-\-json\fR, \fB\-t

Generate text output for any data definitions.

.TP

.B \-\-cpp\fR, \fB\-c

Generate C++ headers for tables/structs.

.TP

.B \-\-go\fR, \fB\-g

Generate Go files for tables/structs.

.TP

.B \-\-java\fR, \fB\-j

Generate Java classes for tables/structs.

.TP

.B \-\-dart\fR, \fB\-d

Generate Dart classes for tables/structs.

.TP

.B \-\-ts\fR, \fB\-T

Generate TypeScript code for tables/structs.

.TP

.B \-\-csharp\fR, \fB\-n

Generate C# classes for tables/structs.

.TP

.B \-\-python\fR, \fB\-p

Generate Python files for tables/structs.

.TP

.B \-\-lobster

Generate Lobster files for tables/structs.

.TP

.B \-\-lua\fR, \fB\-l

Generate Lua files for tables/structs.

.TP

.B \-\-rust\fR, \fB\-r

Generate Rust files for tables/structs.

.TP

.B \-\-php

Generate PHP files for tables/structs.

.TP

.B \-\-kotlin

Generate Kotlin classes for tables/structs.

.TP

.B \-\-jsonschema

Generate Json schema.

.TP

.B \-\-swift

Generate Swift files for tables/structs.

.TP

.B \-\-nim

Generate Nim files for tables/structs.

.TP

.B \-o\ \fIPATH

Prefix

.I PATH

to all generated files.

.TP

.B \-I\ \fIPATH

Search for includes in the specified path.

.TP

.B \-M

Print

.BR make (1)

rules for generated files.

.TP

.B \-\-version

Print the version number of

.B flatc

and exit.

.TP

.B \-\-strict\-json

Strict JSON: field names must be\ / will be quoted,

no trailing commas in tables/vectors.

.TP

.B \-\-allow-non-utf8

Pass non-UTF-8 input through parser and emit nonstandard

.BI \\\\\\\\ x

escapes in JSON.

(Default is to raise parse error on non-UTF-8 input.)

.TP

.B \-\-natural\-utf8

Output strings with UTF-8 as human-readable strings.

By default, UTF-8 characters are printed as

.BI \\\\\\\\u XXXX

escapes.

.TP

.B \-\-defaults\-json

Output fields whose value is the default when writing JSON.

.TP

.B \-\-unknown\-json

Allow fields in JSON that are not defined in the schema.

These fields will be discared when generating binaries.

.TP

.B \-\-no\-prefix

Don\(cqt prefix enum values with the enum type in C++.

.TP

.B \-\-scoped\-enums

Use C++11 style scoped and strongly typed enums.

Also implies

.BR \-\-no\-prefix .

.TP

.B \-\-no\-emit\-min\-max\-enum\-values

Disable generation of

.B MIN

and

.B MAX

enumerated values for scoped enums and prefixed enums.

.TP

.B \-\-gen\-includes

.RI ( deprecated ),

this is the default behavior.

If the original behavior is required (no include statements) use

.BR \-\-no\-includes .

.TP

.B \-\-no\-includes

Don\(cqt generate include statements for included

schemas the generated file depends on (C++\ / Python).

.TP

.B \-\-gen\-mutable

Generate accessors that can mutate buffers in-place.

.TP

.B \-\-gen\-onefile

Generate single output file for C# and Go.

.TP

.B \-\-gen\-name\-strings

Generate type name functions for C++ and Rust.

.TP

.B \-\-gen\-object\-api

Generate an additional object-based API.

.TP

.B \-\-gen\-compare

Generate

.B operator==

for object-based API types.

.TP

.B \-\-gen\-nullable

Add Clang

.B _Nullable

for C++ pointer.

or

.B @Nullable

for Java

.TP

.B \-\-java\-package\-prefix

Add a prefix to the generated package name for Java.

.TP

.B \-\-java\-checkerframework

Add

.B @Pure

for Java.

.TP

.B \-\-gen\-generated

Add

.B @Generated

annotation for Java

.TP

.B \-\-gen\-jvmstatic

Add

.B @JvmStatic

annotation for Kotlin methods

in companion object for interop from Java to Kotlin.

.TP

.B \-\-gen\-all

Generate not just code for the current schema files,

but for all files it includes as well.

If the language uses a single file for output (by default

the case for C++ and JS), all code will end up in this one file.

.TP

.B \-\-gen\-json\-emit

Generates encoding code which emits Flatbuffers into JSON.

.TP

.B \-\-cpp\-include

Adds an

.B #include

in generated file.

.TP

.B \-\-cpp\-ptr\-type\ \fIT

Set object API pointer type

(default

.BR std::unique_ptr ).

.TP

.B \-\-cpp\-str\-type\ \fIT

Set object API string type

(default

.BR std::string ).

.BR \fIT\fB::c_str() ,

.BR \fIT\fB::length() ,

and

.BR \fIT\fB::empty()

must be supported.

The custom type also needs to be constructible from

.B std::string

(see the

.B \-\-cpp\-str\-flex\-ctor

option to change this behavior).

.TP

.B \-\-cpp-str-flex-ctor

Don\(cqt construct custom string types by passing

.B std::string

from Flatbuffers, but (\fBchar*\fR\ + \fIlength\fR).

.TP

.B \-\-cpp-std\ \fICPP_STD

Generate a C++ code using features of selected C++ standard.

.IP

.B Supported

.I CPP_STD

.B values:

.RS +7n

.IP \(bu 2n

.B c++0x

\(en generate code compatible with old compilers;

.IP \(bu 2n

.B c++11

\(en use C++11 code generator

.RI ( default );

.IP \(bu 2n

.B c++17

\(en use C++17 features in generated code

.RI ( experimental ).

.RE

.TP

.B \-\-cpp\-static\-reflection

When using C++17, generate extra code to provide compile-time

(static) reflection of Flatbuffers types.

Requires

.B \-\-cpp\-std

to be

.RB \(lq c++17 \(rq

or higher.

.TP

.B \-\-object\-prefix

Customise class prefix for C++ object-based API.

.TP

.B \-\-object\-suffix

Customise class suffix for C++ object-based API.

Default value is

.RB \(lq T \(rq.

.TP

.B \-\-go\-namespace

Generate the overriding namespace in Golang.

.TP

.B \-\-go\-import

Generate the overriding import for flatbuffers in Golang

(default is

.RB \(lq github.com/google/flatbuffers/go \(rq).

.TP

.B \-\-go\-module\-name

Prefix local import paths of generated go code with the module name.

.TP

.B \-\-raw\-binary

Allow binaries without

.B file_identifier

to be read.

This may crash

.B flatc

given a mismatched schema.

.TP

.B \-\-size\-prefixed

Input binaries are size prefixed buffers.

.TP

.B \-\-proto\-namespace\-suffix\ \fISUFFIX

Add this namespace to any flatbuffers generated from protobufs.

.TP

.B \-\-oneof\-union

Translate

.B .proto

oneofs to flatbuffer unions.

.TP

.B \-\-keep\-proto\-id

Keep protobuf field ids in generated fbs file.

.TP

.B \-\-proto\-id\-gap

Action that should be taken when a gap between protobuf ids found.

.IP

.B Supported values:

.RS +7n

.IP \(bu 2n

.B nop

\(en do not care about gap

.IP \(bu 2n

.B warn

\(en A warning message will be shown about the gap in protobuf ids

.RI ( default )

.IP \(bu 2n

.B error

\(en An error message will be shown and the fbs generation will be interrupted.

.RE

.TP

.B \-\-grpc

Generate GRPC interfaces for the specified languages.

.TP

.B \-\-schema

Serialize schemas instead of JSON (use with

.BR \-b ).

.TP

.B \-\-bfbs\-comments

Add doc comments to the binary schema files.

.TP

.B \-\-bfbs\-builtins

Add builtin attributes to the binary schema files.

.TP

.B \-\-bfbs\-gen\-embed

Generate code to embed the

.B bfbs

schema to the source.

.TP

.B \-\-conform\ \fIFILE

Specify a schema the following schemas should be an evolution of.

Gives errors if not.

.TP

.B \-\-conform\-includes

Include path for the schema given with

.BR \-\-conform\ \fIPATH .

.TP

.B \-\-filename\-suffix

The suffix appended to the generated file names.

Default is

.BR \(oq _generated \(cq.

.TP

.B \-\-filename\-ext

The extension appended to the generated file names.

Default is language-specific (e.g.,

.RB \(oq .h \(cq

for C++)

.TP

.B \-\-include\-prefix\ \fIPATH

Prefix this path to any generated include statements.

.TP

.B \-\-keep\-prefix

Keep original prefix of schema include statement.

.TP

.B \-\-reflect\-types

Add minimal type reflection to code generation.

.TP

.B \-\-reflect\-names

Add minimal type/name reflection.

.TP

.B \-\-rust\-serialize

Implement

.B serde::Serialize

on generated Rust types.

.TP

.B \-\-rust\-module\-root\-file

Generate rust code in individual files with a module root file.

.TP

.B \-\-root\-type\ \fIT

Select or override the default root_type.

.TP

.B \-\-require\-explicit\-ids

When parsing schemas, require explicit ids

.RB ( id:\ \fIx ).

.TP

.B \-\-force\-defaults

Emit default values in binary output from JSON.

.TP

.B \-\-force\-empty

When serializing from object API representation,

force strings and vectors to empty rather than null.

.TP

.B \-\-force\-empty\-vectors

When serializing from object API representation,

force vectors to empty rather than null.

.TP

.B \-\-flexbuffers

Used with

.RB \(lq binary \(rq

and

.RB \(lq json \(rq

options, it generates

data using schema-less FlexBuffers.

.TP

.B \-\-no\-warnings

Inhibit all warning messages.

.TP

.B \-\-warnings\-as-errors

Treat all warnings as errors.

.TP

.B \-\-cs\-global\-alias

Prepend

.RB \(lq global:: \(rq

to all user generated csharp classes and structs.

.TP

.B \-\-cs\-gen\-json\-serializer

Allows (de)serialization of JSON text in the Object API.

(requires

.BR \-\-gen\-object\-api ).

.TP

.B \-\-json\-nested\-bytes

Allow a

.B nested_flatbuffer

field to be parsed as a vector of bytes in JSON,

which is unsafe unless checked by a verifier afterwards.

.TP

.B \-\-ts\-flat\-files

Generate a single typescript file per

.B .fbs

file.

Implies

.BR \-\-ts\-entry\-points .

.TP

.B \-\-ts\-entry\-points

Generate entry point typescript per namespace.

Implies

.BR \-\-gen\-all .

.TP

.B \-\-annotate\-sparse\-vectors\ \fISCHEMA

Don\(cqt annotate every vector element.

.TP

.B \-\-annotate\ \fISCHEMA

Annotate the provided

.I BINARY_FILE

with the specified

.I SCHEMA

file.

.TP

.B \-\-no\-leak\-private\-annotation

Prevents multiple type of annotations within a Fbs

.I SCHEMA

file.

Currently this is required to generate private types in Rust.

.TP

.B \-\-python\-no\-type\-prefix\-suffix

Skip emission of Python functions that are prefixed with typenames

.TP

.B \-\-python\-typing

Generate Python type annotations

.TP

.B \-\-file\-names\-only

Print out generated file names without writing to the files

.SH EXAMPLES

.EX

.B flatc\ \-c\ \-b\ schema1.fbs\ schema2.fbs\ data.json

.EE

.SH "SEE ALSO"

.UR https://google.github.io/flatbuffers

Official documentation

.UE