The task interface needs the ABI switch, and a task program runs with it (0.1.1)

[Sunrisepeak]

openkal.task needs -pthread on Emscripten, and -pthread changes the module configuration of every translation unit in the link, so it cannot be a flag of this package's own units. mcpp 2026.9.12.2 (mcpp-community/mcpp#619) carries the switch as a typed member of the consumer's root manifest:

[target.'cfg(os = "emscripten")'.abi]
threads = true

Changes

• The threads feature declares requires_abi = { threads = true } instead of adding -pthread to src/**. A consumer that activates the feature without the table is refused before anything compiles, and the refusal names the feature and the table.

• The README section that recorded "mcpp has no channel for a flag that applies to a whole dependency graph" is corrected. The failure measured on 2026-09-11 was -pthread in the consumer's per-package cxxflags, which does not reach the specification package's module. A graph-wide channel existed; what was missing was a way to scope it to a target and to let this feature state its requirement.

• CI's task gate asserts three things:

  1. no task symbol without the feature;
  2. the refusal without the switch, naming the feature;
  3. with the switch, eight task symbols and a program that starts a task and joins it exiting 0 under node.

  The conformance step's comment states why task stays outside the suite's interface list: the suite's consumer manifest is generated by the specification's runner.

• The CI engine pin moves to 2026.9.12.2.

• The version moves to 0.1.1, so the index can publish the change.

Measurement

Measured 2026-09-12 with emsdk 6.0.9 and a development build of mcpp 2026.9.12.2, on a consumer of this checkout by path:

without the table:  exit 2
error: `openkal-emscripten` requires the artefact's ABI to have threads (feature `threads`), and this build does not state it.

with the table:     build exit 0; `mcpp run --target wasm32-emscripten` exit 0

The program exits 0 only if the parallel property is set, kal_task_start succeeds, kal_task_join succeeds and the task ran.

Compatibility

An mcpp older than 2026.9.12.2 reports requires_abi as an unknown feature key and skips it, so the feature no longer adds -pthread. The threads feature was not usable end to end on those versions (the module configuration mismatch above), so no working configuration is lost.