package cmdliner-stdlib

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A collection of cmdliner terms to control OCaml runtime parameters

Install

Dune Dependency

Authors

Maintainers

Sources

cmdliner-stdlib-1.0.0.tbz
sha256=5e8986fd8d86a6df0e5031e58ac2dafd738c41767ce4ca08059659246ce8313a
sha512=c693e60d79f0977122afad7b5dc1a273db692985c47b40d9a47372b3c3fbbfbce1a33d5808dcd0df21c45b4341d993c145e0033716cf07dfd20dd2ad5ba21d8f

Description

Cmdliner-stdlib is a package that provides a collection of cmdliner terms to control the OCaml runtime parameters. This is typically done with environment variables, but there are situations where such an environment is not accessible, like in MirageOS. This package enables the configuration and manipulation of runtime parameters in these contexts, improving the flexibility of applications built on these platforms.

Tags

org:mirage

Published: 04 Jul 2023

README

cmdliner-stdlib

The cmdliner-stdlib package is a collection of cmdliner terms that help control OCaml runtime parameters, usually configured through the OCAMLRUNPARAM environment variable. The package provides command-line options for controlling features like backtrace, hash table randomization, and garbage collector tuning.

Installation

You can install the package using opam:

opam install cmdliner-stdlib

Usage

You can use these command-line arguments to:

  • enable/disable backtraces;

  • enable/disable table randomization, for better security and prevent collision attacks; and

  • control the OCaml garbage collector as described in detail in the GC control documentation.

open Cmdliner

let cmd = Cmd.v (Cmd.info "hello") (Cmdliner_stdlib.setup ())
let () = exit (Cmd.eval cmd)

You can then use command-line options to change parameters of the OCaml runtime. For instance, to enable backtraces and change the GC allocation policy to "first fit":

$ dune exec -- ./hello.exe --allocation-policy=first-fit --backtrace=true

You can disable some of these arguments. For instance, to disable GC control use:

   Cmdliner_stdlib.setup ~gc_control:None ()

Or to change the default allocation policy to be first-fit:

  let default = Gc.get () in
  let gc_control = Some { default with allocation_policy = 1 } in
  Cmdliner_stdlib.setup ~gc_control ()

Contributions

We welcome contributions, bug reports, and feature requests. Please visit our GitHub repository for more information.

Dependencies (3)

  1. cmdliner >= "1.0.0"
  2. dune >= "2.9.0"
  3. ocaml >= "4.08.0"

Dev Dependencies

None

Used by

None

Conflicts

None

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