MirageOS on OCaml 5 - Community - OCaml

On behalf of all the numerous developers involved, it’s my pleasure to announce that the MirageOS ecosystem has seen the long-running work to port to OCaml 5 come to fruition: ocaml-solo5 v1.0 is now using OCaml 5.2.1!

ocaml-solo5 is an OCaml cross compiler for producing Solo5 unikernels. Solo5 is the basis for MirageOS unikernels when they are not compiled as programs to run on a regular OS.

ocaml-solo5 responds to specific unikernel constraints. In particular it provides a placeholder for the standard C library that is complete enough that we can build the OCaml runtime without a full POSIX system to support it. That OCaml runtime can then be linked statically to OCaml programs in order to produce unikernels.

These constraints require us to keep track of developments of the OCaml compiler and particularly of its runtime. The major changes coming with OCaml 5 have required quite a lot of work (over 1 year) to bring our cross compiler up-to-date.

It should be noted that ocaml-solo5 is restricted to a single domain but it makes it possible to use the effects introduced with OCaml 5.

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