fortran-lang / fpm

Fortran Package Manager (fpm)

https://fpm.fortran-lang.org

MIT License

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Check that Fortran sources run; Robust Fortran features #1051

Closed perazz closed 1 week ago

perazz commented 2 weeks ago

This PR enables fpm to perform checks on supported Fortran features at project build time, with the aim to improve/enable [Fortran features]() support.

[x] implement, test a check_fortran_source_runs compiler property to run Fortran sources on-the-fly, similar to CMake's CheckFortranSourceRuns
[x] implement with_qp fortran feature that checks for quad-precision real kind support
[x] implement with_xdp fortran feature that checks for 80-bit extended-precision real kind support

Later, I plan to add conditional fortran features quad-precision and extended-precision to the fortran table. We should decide on a suitable logic: automated setting of preprocessor flags such as WITH_QP and WITH_XDP every time? or just if required in the fortran table? etc.

Context:

864

https://github.com/fortran-lang/stdlib/pull/821 cc: @jvdp1 @jalvesz @awvwgk @fortran-lang/fpm @fortran-lang/stdlib

perazz commented 2 weeks ago

Will merge soon as there are no comments. Thanks.

jalvesz commented 2 weeks ago

Hi @perazz I wanted to ask something before and got busy in between, sorry.

We should decide on a suitable logic: automated setting of preprocessor flags such as WITH_QP and WITH_XDP every time? or just if required in the fortran table?

Here, should it be understood that setting the option in the fortran table would be equivalent to adding a macro option under preprocessor.cpp ['-DWITH_QP'] for instance? in the sense that one should not need to added by hand? If that is the case LGTM. I did not fully understood the alternative.

perazz commented 2 weeks ago

Thanks @jalvesz, the current PR does not address that yet as it just builds the internal capability to check that the current compiler supports qp and xdp by compiling and running a small program. That is exactly the aim I would like to address further in a separate PR. I think the options are:

Always generate standardized macros when those features are supported -> I'm very much in favor at least for these ones, WITH_QP, WITH_XDP, WITH_MPI, etc. so that conditional programming is always enabled, and that also consolidates standardized macros from fpm
Add these as mandatory features in the fortran table. In other words, if one package may require a specific precision to be supported

[fortran]
quadruple-precision=true

and fpm can check whether that is supported by the current compiler, and stop if it is not the case.

jalvesz commented 2 weeks ago

Cristal clear! thanks!