ml-explore/mlx

Why is `MLX_BUILD_METAL` disabled on iOS

Open

#3493 opened on May 8, 2026

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enhancementgood first issue

Description

When targeting iOS, the CMAKE_SYSTEM_NAME fails the Darwin equality check, resulting in MLX_BUILD_METAL being disabled. Does MLX Metal not work on iOS?

Contributor guide

Tech stack
cpp
Domain
build systemmobile
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
fresh
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
CMakeiOS developmentMetal framework
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
50
Research direction
Investigate the CMake build files (e.g., CMakeLists.txt) to find where `MLX BUILD METAL` is set. The condition checks `CMAKE SYSTEM NAME` for `Darwin`, which fails on iOS because iOS reports a different system name. Review the issue comments and linked code to understand the intended behavior. Consider modifying the condition to also include iOS or define a separate flag for Metal on iOS.