C ABI / FFI

Stable extern "C" entry points for non-Rust runtimes. The Rust crate remains the full API; the shared library exposes a narrow subset.

Status

ABI v1 behind Cargo feature tetration-ffi:

Symbol	Role
tet_abi_version	Must match #define TET_ABI_VERSION in header
tet_open / tet_close	Read-only .tet handle
tet_last_error / tet_clear_error	Thread-local UTF-8 error text
tet_summary_json	Catalog summary JSON
tet_query_json	Query document JSON → QueryResponse JSON
tet_verify_json	Quick verify report JSON
tet_string_free	Free buffers from *_json

Header: include/tetration.h

Build

# Lean shared library (no HDF5 / NetCDF)
cargo build --release --no-default-features --features tetration-ffi

Artifacts:

Platform	Library
Linux	target/release/libtetration.so
macOS	target/release/libtetration.dylib
Windows	target/release/tetration.dll

C example

cargo build --release --no-default-features --features tetration-ffi

cc -std=c11 -Wall -Wextra -I include examples/ffi_query.c \
  -L target/release -ltetration -o target/release/ffi_query

# macOS
DYLD_LIBRARY_PATH=target/release target/release/ffi_query sample.tet

Design principles

1. JSON for documents — query in and structured result out match tet query -x
2. Opaque handles — TetHandle owns mmap + path
3. Lean library — build with default-features = false when you only need open/query/verify
4. TET_ABI_VERSION — bump on breaking C symbol changes

Out of v1 ABI: convert/import, writer session, GPU device selection, query history.

Python bindings

Official Python bindings (tet-py) use PyO3 over the Rust crate, not the C ABI. Install from PyPI: pip install tet-py. See Python overview.

Release archives

GitHub Releases attach per-platform FFI archives on tag push (v*). See upstream docs/ffi.md.