# running-process-platform-internal
Internal, published host-mechanics boundary for running-process. Its public
surface is intentionally small; product policy remains in the caller crates.
Deprecated 4.x PTY trait accessors remain source-compatible until 5.0, but
platform mechanics never consume their primitive values. Native PTY control
state must stay captured inside concrete operations; the neutral facade may not
introduce descriptor/HANDLE payload structs or tokens.
The established 4.x broker post-Hello callback, client stream returns, and
pre-bound async SESSION listener entry points likewise remain source-compatible
until 5.0. A hidden crate-root adapter may convert an opaque IPC stream only at
those public return/callback boundaries, and the facade conversion trait may
accept the legacy listener on entry. The neutral `platform::ipc` facade never
returns the concrete transport type, and new callers must use the opaque
transport.
`src/lib.rs` is the only host selector. Neutral capability indexes live in
`src/platform/`; their private Windows, Linux, and macOS implementations are
selected behind that boundary.