Jason Larabie 52b6c66fa1
Add C++ Bindings (#3544)
# Description of Changes

This adds C++ server bindings (/crate/bindings-cpp) to allow writing C++
20 modules.

- Emscripten WASM build system integration with CMake
- Macro-based code generation (SPACETIMEDB_TABLE, SPACETIMEDB_REDUCER,
etc)
- All SpacetimeDB types supported (primitives, Timestamp, Identity,
Uuid, etc)
- Product types via SPACETIMEDB_STRUCT
- Sum types via SPACETIMEDB_ENUM
- Constraints marked with FIELD* macros

# API and ABI breaking changes

None

# Expected complexity level and risk

2 - Doesn't heavily impact any other areas but is complex macro C++
structure to support a similar developer experience, did have a small
impact on init command

# Testing

- [x] modules/module-test-cpp - heavily tested every reducer
- [x] modules/benchmarks-cpp - tested through the standalone (~6x faster
than C#, ~6x slower than Rust)
- [x] modules/sdk-test-cpp
- [x] modules/sdk-test-procedure-cpp
- [x] modules/sdk-test-view-cpp  
- [x] Wrote several test modules myself
- [x] Quickstart smoketest [Currently in progress]
- [ ] Write Blackholio C++ server module

---------

Signed-off-by: Jason Larabie <jason@clockworklabs.io>
Co-authored-by: clockwork-labs-bot <clockwork-labs-bot@users.noreply.github.com>
Co-authored-by: Ryan <r.ekhoff@clockworklabs.io>
Co-authored-by: John Detter <4099508+jdetter@users.noreply.github.com>
2026-02-07 04:26:45 +00:00

1.3 KiB

sdk-test-cpp C++ test module

Exercise the functionality of the SpacetimeDB C++ bindings API surface, modeling all combinations of types, with several examples of tables, indexes, and reducers.

Used to validate C++ bindings functionality and ensure parity with Rust/C# implementations.

Note: Mirrors functionality from modules/sdk-test and modules/sdk-test-cs.

Building

cd modules/sdk-test-cpp

spacetime build -p .

The built WASM module will be at build/lib.wasm.

Testing

# Start SpacetimeDB
spacetime start

# Publish the module
spacetime publish . test-db --delete-data

# Verify module schema
spacetime describe test-db

# Call example reducer
spacetime call test-db add_player '"Alice"'

# View logs
spacetime logs test-db -f

Module Contents

lib.cpp contains comprehensive testing of:

  • All primitive types (integers, floats, bool, string)
  • Special types (Identity, ConnectionId, Timestamp, TimeDuration)
  • Collections (vectors, optionals)
  • Custom structs and enums
  • Table constraints (PrimaryKey, Unique, AutoInc, indexes)
  • Lifecycle reducers (init, connect, disconnect)
  • CRUD operations

For C++ bindings usage documentation, see crates/bindings-cpp/.