---
name: "Gc.Tweak"
section: "3o"
platform: "linux"
package: "ocaml"
version: "5.5.0-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/Gc.Tweak"
---

# Gc.Tweak(3o)

GC Tweaks are unstable and undocumented configurable GC parameters, primarily intended for use by GC developers.

## NAME

Gc.Tweak - GC Tweaks are unstable and undocumented configurable GC parameters, primarily intended for use by GC developers.

## Module

Module   Gc.Tweak

## Documentation

Module **Tweak**\
  :  **sig end**

GC Tweaks are unstable and undocumented configurable GC parameters, primarily intended for use by GC developers.

As well as using Gc.Tweak.set "foo" 42, they can also be configured in OCAMLRUNPARAM, using the following syntax:

OCAMLRUNPARAM='Xfoo=42'

Additionally, OCAMLRUNPARAM=Xhelp will show the available GC tweaks.

**Since** 5.5

*val set* :  **string -\> int -\> unit**

Change a parameter. Raises Invalid\_argument if no such parameter exists

*val get* :  **string -\> int**

Retrieve a parameter value. Raises Invalid\_argument if no such parameter exists

*val list\_active* :  **unit -\> (string \* int) list**

Returns the list of parameters and their values that currently have non-default values