Conveniently, CMake has built-in support for requiring a specific C/C++ language standard in a compiler-independent way.
We already set a requested C and CXX standard level here: https://gitlab.ambermd.org/amber/amber/-/blob/master/cmake/CompilationOptions.cmake#L49
All we need to do to make this mandatory is add these lines:
set(CMAKE_C_STANDARD_REQUIRED TRUE)
set(CMAKE_CXX_STANDARD_REQUIRED TRUE)
This will cause CMake to error out if it determines the compiler in use does not support the requested standards. More details for those interested: https://cmake.org/cmake/help/latest/manual/cmake-compile-features.7.html
Also, the code you pushed has the right idea but I would recommend wrapping it in a check for what compiler is actually in use. Something like this:
if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS 6.0)
message(FATAL_ERROR "Amber requires at least gcc-6.0")
endif()
endif()
That way you can specify a different minimum version for each compiler.
Hope that makes sense,
Jamie
-----Original Message-----
From: David A Case <david.case.rutgers.edu>
Sent: Tuesday, January 25, 2022 5:43 PM
To: AMBER Developers Mailing List <amber-developers.ambermd.org>
Subject: Re: [AMBER-Developers] Pmemd no longer compiling with older GCC (4.8.5)
On Tue, Jan 25, 2022, David Case wrote:
>Googling on "cmake minimum gnu version" shows how easy this is to
>implement
>there: cmake handles the hard part of even finding the GNU version --
>compare this to the 100+ lines of code in the old configure2 script to
>handle this task.
Update: I've pushed a new branch, minimum_compiler_check, that implements simple checks on g++ and gfortran. The error messages should be expanded to point users to documentation about how to fix the problem. And, the check on c++ might be changed to require a specific std-cxx version, but I don't immediately see how to implement that check right at the beginning of the cmake run, where it will do the most good.
Dan: can you try this branch on your 4.8.5 system? Think about how we might make the messages as easy as possible to understand.
...thx...dac
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Received on Tue Jan 25 2022 - 21:30:02 PST
