Ocamlnet 4 Reference Manual : Netplex_encap

# Module Netplex_encap

    module Netplex_encap: sig .. end

Type-safe marshalling between processes of the same executable

This is a pragmatic approach to type-safe marshalling. We define `type encap` as an arbitrary value that carries a type identifier with it. The type identifier is generated when the functor `Netplex_encap.Make_encap` is applied. Every instantiation of this functor generates a new type identifier.

The idea is then that an `encap` value can be marshalled to another process using `Marshal`, and when it is unwrapped the type identifier is checked. Unwrapping is only successful when the `unwrap` function from the same functor instantiation is used as the `wrap` function.

This module is incompatible with:

- Marshalling to processes running a different executable
- Marshalling to processes that are dynamically loading modules
- The functor must be instantiated at program initialization time. Especially this must not happen in `let module` expressions.

Only some of these assumptions can be checked at runtime by this implementation.

    exception Type_mismatch

Raised when an encapulated type is tried to be unwrapped by the wrong encapsulation module

    type encap

An encapsulated value with a type identifier

    module type TYPE = sig .. end

Just a (monomorphic) type `t`

    module type ENCAP = sig .. end

    module Make_encap: functor (T : TYPE) -> ENCAP  with type t = T.t

Create an encapsulation module