cppfmtlib/fmt #4684Not a task: already works

No support for Installing C++20 module Target separate from Regular compiled Target

envgap__fmtlib__fmt-4684

Original GitHub issue ↗Dated source checkout ↗Opened 2026-02-24

01 / FAILURE SIGNATURE

As reported upstream

No identifying execution failure has been captured.

Not a benchmark task.

The project already builds and runs before the fix, so there is nothing to repair.

02 / ENVIRONMENT RECIPE

Base commit: fca04455651600dd4dbf4fc6d97cea103d1ae909
Manifest: CMakeLists.txt
Reproduce: Awaiting issue-specific recipe
Run under trace: Awaiting a meaningful runtime command

03 / ORIGINAL ISSUE TEXT

fmtlib/fmt #4684 · read the original issue

FMT_MODULE flag creates two different versions of the same CMake Target `fmt::fmt`

CMake, since version 3.28 supports installation of C++ Modules. 

It is indeed possible to install and use the module version of the library by setting `FMT_MODULE=ON` before installing.

For widespread support for C++ Modules, we likely need a new CMake Target  specific for modules, which can be installed alongside the regular `fmt::fmt` target and the `fmt::fmt-header-only` targets.

Continue on GitHub ↗

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