1# @ajax/mesh-abi-placement
2
3Placement across machines: capabilities, modes, split parts and the show region (SH_*).
4
5Part of the mesh contract: the memory, control, snapshot and peer protocols shared by meshd, its GPU
6programs (CUDA kernels, wasm lanes, native workers) and the tools. Every side compiles the same
7definitions, so an offset can never disagree.
8
9```c
10#include "mesh/abi/placement.h"
11```
12
13## Ported from
14
15[alpha-rust-mesh](https://github.com/rsafier/alpha-rust-mesh) (Richard Safier, MIT): crates/mesh-abi/src/v2.rs: PLACE_CAP_NONE, PLACE_CAP_PIN, PLACE_CAP_SPLIT, PLACE_CAPS, PLACE_LOCAL, PLACE_PIN, PLACE_SPLIT, PLACES, … (19 in all).
16
17Names: Rust's `NAME` is `MESH_NAME`; a constant of a Rust module `m` is `MESH_M_NAME` (unless it already starts with `M_`); a function `f` is `mesh_f` (`mesh_m_f`). Offsets that are `usize` in the Rust are plain integer constants or `size_t` results, `u32` constants carry a `u` suffix, `u64` use `UINT64_C`.
18
19## Device code
20
21The header is freestanding (`<stdint.h>`, `<stddef.h>`, `<stdbool.h>` only): it compiles for the host, `nvptx64-nvidia-cuda` and `wasm32`. Functions the Rust marks `const fn` are `static inline` here. Its tables (string names, field lists) live in `src/`, so device code that uses them links the package for that target.
22
23## Tests
24
25- `tests/constants.c`: every constant against the value the Rust prints (25 checks)
26- `tests/golden.c`: its functions against 5 vectors computed by the Rust on the same inputs
27
28## Licence
29
30MIT. See the repository's LICENSE.