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Every generated library exports both ABIs side by side; spell out the choice in the example READMEs: the native (pure-C) ABI is the default for same-process / local calls (flat C structs, zero serialization), while the CBOR ABI exists solely for inter-process communication (different process or machine). In a shared address space CBOR is pure overhead, so prefer native locally. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
timer example
This example is a self-contained Nimble project demonstrating how to import nim-ffi and use the .ffiCtor. / .ffi. abstraction.
Two ABIs, one library
Every generated library exports two ABIs side by side, and you choose per call site:
| ABI | Header / symbols | Use it for |
|---|---|---|
| Native (pure C) | <lib>.h / <name> |
Same-process / local calls. Flat C structs by value, zero serialization. |
| CBOR | <lib>_cbor.h / <name>_cbor |
Inter-process communication only — a different process or machine, where the request must be serialized to cross the boundary. |
In a shared address space the CBOR round-trip is pure overhead, so default to the native ABI locally and reach for CBOR only when you actually cross a process/machine boundary (see ipc/). The per-language examples below: native C (c_bindings/), native Go (go_bindings/), native/CBOR C++ (cpp_bindings/), CBOR Rust (rust_client/), and CBOR-over-socket IPC (ipc/).
Usage
-
Change into the example directory:
cd examples/timer -
Install the local
ffidependency:nimble install -y ../.. -
Build the example library:
nimble build -
Generate bindings:
nimble genbindings_rust nimble genbindings_cpp
Rust example clients
The Rust client lives in examples/timer/rust_client.
-
Run the sync example:
cd examples/timer/rust_client cargo run --bin rust_client -
Run the Tokio example:
cd examples/timer/rust_client cargo run --bin tokio_client
C++ example
The generated C++ example lives in examples/timer/cpp_bindings.
Build and run it with:
cd examples/timer/cpp_bindings
cmake -S . -B build
cmake --build build
./build/example