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Why is g++ necessary to compile GHC?

    • Closed Issue created by Ben Gamari @bgamari

    Simonpj noted after a system upgrade that GHC failed to build unless g++ is installed. libffi's configure otherwise failed with

    configure:13086: checking how to run the C++ preprocessor
configure:13113: gcc -E  conftest.cpp
gcc: error trying to exec 'cc1plus': execvp: No such file or directory

    Why is this necessary?

    Trac metadata
    Trac field Value
    Version 8.2.1
    Type Bug
    TypeOfFailure OtherFailure
    Priority normal
    Resolution Unresolved
    Component Compiler
    Test case
    Differential revisions
    BlockedBy
    Related
    Blocking
    CC
    Operating system
    Architecture
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    • Ben Gamari changed weight to 5

      changed weight to 5

    • Ben Gamari added Tbug Trac import labels

      added Tbug Trac import labels

    • Ben Gamari closed

      closed

    • Ben Gamari
      Ben Gamari @bgamari ·
      Author Maintainer

      Right after I hit "submit" the reason became clear: libffi is explicitly looking for a C++ preprocessor. Consequently it uses .cpp as the extension for the source file it feeds gcc. This compels gcc to go looking for a C++ compiler. It looks like we will just need to document the g++ requirement.

      Trac metadata
      Trac field Value
      Resolution Unresolved → ResolvedWon'tFix
    • Simon Peyton Jones
      Simon Peyton Jones @simonpj ·
      Developer

      But does libffi really NEED a C++ preprocessor? Or is it accidental?

      If deliberate, then yes, let's just document it. Even if accidental, perhpas it's in a code base we don't control in which case we are stuck with it.

    • Ben Gamari
      Ben Gamari @bgamari ·
      Author Maintainer

      I can't speak to whether it needs a C++ preprocessor. That being said, it is indeed a codebase which we have no control over. Moreover, it is sadly rather under-maintained so getting them to drop the dependency if it's not needed will be difficult.

    • Ben Gamari added Pnormal label

      added Pnormal label

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