zero

Reference

Target Capabilities

Current host and target-neutral capability boundaries.

What Targets Mean Today

The current compiler has a small explicit target table. Inspect it with:

zero targets

The JSON includes:

  • schemaVersion
  • current host
  • each target's hosted flag
  • aliases
  • mapped C target
  • capabilities

Host Capabilities

Only the current host target exposes hosted process capabilities:

  • args
  • env
  • fs
  • memory
  • stdio

Non-host targets currently expose the target-neutral subset:

  • memory
  • stdio

This means hosted std.fs examples are valid on the host target. Memory-only packages can still build for target-neutral outputs.

Hosted File I/O

This succeeds on the host target:

zero check examples/resource-cli

The same hosted filesystem surface fails clearly on a non-host target:

zero check --json --target linux-musl-x64 conformance/native/fail/std-fs-target-unsupported.0

The diagnostic is TAR002 with repair id remove-hosted-fs-or-use-host-target.

Target-Neutral Memory

std.mem.copy and std.mem.fill do not require hosted filesystem support:

zero build --target linux-musl-x64 examples/memory-package --out .zero/out/memory-package

Use graph and size JSON to inspect target facts:

zero graph --json --target linux-musl-x64 examples/memory-package
zero size --json --target linux-musl-x64 examples/memory-package

Both outputs include requiresCapabilities, targetSupport, and stdlibHelpers.

Repair Commands

Use zero explain for human and JSON explanations:

zero explain TAR002
zero explain --json TAR002

Use fix-plan mode to inspect the canonical repair without editing files:

zero fix --plan --json --target linux-musl-x64 conformance/native/fail/std-fs-target-unsupported.0