From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id 95E143858C42; Sat, 30 Dec 2023 19:15:20 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 95E143858C42 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1703963720; bh=twfkJY7hlJMrStaE5Rk92g0e3FbIdWyQn6RHHAPt2Ls=; h=From:To:Subject:Date:In-Reply-To:References:From; b=Aqbf0I1O9G1VttxXPhd2P+cgKw9zJxUxaYM0FUPabjpyyB8nUoFdvnH5jVBlz8qqD 0rXM4kyWUdlb32rEKPWsLI25lwX390g5FpyzCzduWFTEfQpV10vcSaoWMh8v2dTXmX bi69NOpgKN3rcnIf9EOtg8IGLAZqFTK0U59Zr3hg= From: "bugzilla.gcc at me dot benboeckel.net" To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/105467] Dependency file produced by C++ modules causes Ninja errors Date: Sat, 30 Dec 2023 19:15:19 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: c++ X-Bugzilla-Version: 11.2.0 X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: bugzilla.gcc at me dot benboeckel.net X-Bugzilla-Status: UNCONFIRMED X-Bugzilla-Resolution: X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 List-Id: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D105467 --- Comment #8 from Ben Boeckel --- > Some people even claim that properly supporting Make to build C++ modules= is not possible if you want to make it actually production quality and rel= iable. It is possible, but, AFAIK, requires at least one level of recursive make (= to deal with the dynamic files). Note that CMake also generates POSIX Make and only uses GNU-specific things to disable things like builtin rules. > GNU make still is the most common usage for build systems out there. Overall? Sure; I don't have data to say otherwise. For C++ modules? Highly unlikely unless autoconf/automake started relying on the non-GNU `fdep` [1] project. My concerns include: - tools have learned to read the *restricted* syntax historically used by `= -MF` output and would need to grow new logic to deal with the `+=3D` usage - the variable name is hard-coded I think the following flags make sense to add: - `-Mmodules` to explicitly request this extra information - `-Mno-modules` to suppress it - `-MMV varname` to select the variable name used (though maybe `-Mc++module-variable=3D` is better) > Anyways gcc should work best with gnu software and cmake is not at all gn= u software and it competes with autoconf and automake which are gnu tools. I eagerly await C++ module support in autoconf and automake in that case. AFAIK, the support is in GNU make only and significant infrastructural supp= ort is missing from autoconf/autotools to reliably support them (namely things = like installation assistance, enforcing visibility of modules between libraries,= and not using stale module files). > Cmake is less portable than the autotools. There is a significant set of platforms that CMake supports that autotools = does not, but yes=E2=80=A6CMake certainly supports fewer total number platforms = than autotools (though when weighted by relevance=E2=80=A6). I'd say there's not= a total ordering here. [1] https://gitlab.mpcdf.mpg.de/elpa/elpa/-/tree/master/fdep FD: CMake developer and primary implementer of C++ module support in it.=