Struct HostFunctions 

pub struct HostFunctions(/* private fields */);

A collection of host functions that can be supplied to a sandbox constructor (e.g. MultiUseSandbox::from_snapshot). A collection of host functions that can be supplied to a sandbox constructor (e.g. crate::MultiUseSandbox::from_snapshot) to expose host-side functionality to the guest.

Use HostFunctions::default to start with the standard HostPrint function pre-registered (matches the registry that the regular UninitializedSandbox → evolve() path constructs), or HostFunctions::empty to start with an empty registry.

Add additional host functions via the crate::func::Registerable trait, just as you would on an UninitializedSandbox.

// Default: HostPrint already registered.
let mut funcs = HostFunctions::default();
funcs.register_host_function("Add", |a: i32, b: i32| Ok(a + b))?;

Implementations

impl HostFunctions

pub fn empty() -> Self

Create an empty HostFunctions with no host functions registered.

Most callers want HostFunctions::default instead, which pre-registers the standard HostPrint function. An empty registry will fail snapshot validation against any snapshot that captured HostPrint, and any guest code that tries to printf into an empty registry will get an EIO from write(2).

Trait Implementations

impl Default for HostFunctions

fn default() -> Self

Create a HostFunctions pre-populated with the standard HostPrint function (writes UTF-8 strings to the host’s stdout in green).

This matches the default registry installed by UninitializedSandbox::new(), so a snapshot taken from a regular sandbox can be loaded with MultiUseSandbox::from_snapshot(snap, HostFunctions::default(), None) without registering anything else.

Use HostFunctions::empty for an empty registry.

impl Registerable for HostFunctions

fn register_host_function<Args: ParameterTuple, Output: SupportedReturnType>( &mut self, name: &str, hf: impl Into<HostFunction<Output, Args>>, ) -> Result<()>

Register a primitive host function