Use GitHub actions to compile BaM executable under MacOS

[benRenard]

There is already a workflow for this, but at the moment the windows exe crashes during computations when run on a local machine (although it does run to give the version tag or the help, it also runs on the github virtual machine, and there is no problem with the linux version).

[MartinMorlot]

Hi ben,

This is something I could look into when I find the time to do so, as I find it quite fun. (In general, I love OS tinkering as a Hobby), I think the first step is to get one of the actions working (say Linux) then move to the windows version (which seems from what I was reading online, a tad more complicated as windows version specific. Do we have an idea of for which version, we should compile? (say 10 and 11?)

[benRenard]

Feel free to go ahead ! It's not part of my favorite hobbies to be honest...

There is already an action running here. From memory, the status is as follows:

• It works if you do runs-on: ubuntu-latest: the exe compiles OK, and it runs fine (on my Ubuntu machine at least).
• It half-works with runs-on: windows-latest (or other windows flavors): the exe compiles OK, it runs fine for elementary tasks such as BaM --version or BaM --help, but it crashes if you try to run a BaM case study (on Ivan's windows machine).

I haven't investigated it further, in part because I don't have a windows machine handy, in part because, well, it's not a hobby of mine. But it would be great to have this running for all OSes, Mac included!

[IvanHeriver]

Hi,

I was successfull in running (fully) an exe created using the gh action on windows 11. The only change made was adding the -static flag to the gfortran compiler. (see line 8 in the makefile here)

I remembered that I always make this edit in the makefile before compiling on my locale machine. Since I don't know how this would affect build on linux, I never commited this edit.

From my understanding, adding the -static flag simply makes the compiler embed all dependancies instead of making an exe relying on exernal dlls that may vary depending on machins/environment. I think it should be safe to use the -static flag on linux as well but it should be tested.

[benRenard]

I tested adding the -static flag on Ubuntu and this seems to work as expected: the exe size increased from 2.2 to 4 Mo due to the static linking, and it runs fine on a BaRatin test. So it looks like I should commit the updated makefile including the -static flag, and we'll have a GitHub action to compile BaM executable under various OSes, which is great !

The only thing I don't like is that I don't really understand what's going on here... in fact -static is not a gFortran flag, it's passed to the linker (ctrl+F "-static" on this page) and I don't quite understand what it's supposed to do. See discussion here: https://fortran-lang.discourse.group/t/makefile-errors-using-gfortran-static-option/3491

So in summary I think we're good to go with the GitHub action, but I would feel more comfortable if we could understand at least superficially what's going on before closing the ticket...

[IvanHeriver]

From some llm discussion, I understand that gfortran is a global tool (a driver) that calls the actual fortran compiler (that creates the actual object files i.e. machine code that is no longer language specific) and the linker specific to the platform (e.g. ld.exe on windows which is used to create the final executable from the object files).

The -static flag is passed to the linker which looks for the static version of dependencies so they are included in the final executable.

Hope that helps clarifying... I did not find any clear web resource explaining that though (at least in a way that I'm able to understand)...

[benRenard]

OK, thanks for the explanation, and for the GitHub actions. So problem solved for linux and windows.

I'm leaving the ticket open for the MacOS problem, the error message is below.

ld: library 'crt0.o' not found
collect2: error: ld returned 1 exit status
make: *** [build_exe] Error 1

Not sure we'll be able to fix this... https://stackoverflow.com/questions/3801011/ld-library-not-found-for-lcrt0-o-on-osx-10-6-with-gcc-clang-static-flag