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gridap / P4est_wrapper.jl

Julia wrappers for p4est library
MIT License
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How to wrap Structs/C-Unions from Julia #1

Open victorsndvg opened 4 years ago

victorsndvg commented 4 years ago

We are using Clang.jl to automate the conversion of p4est headers to Julia bindings. It wraps functions and structs, but some structs are skipped.

Manually wrapping some complex C-structs and C-unions can be non-straightforward, so we need to investigate how to do it correctly.

I was looking for some information in this direction. Links below can be interesting in order to understand how to deal with this issue:

  1. Packed structs and union declarations are not supported by Julia. https://docs.julialang.org/en/latest/manual/calling-c-and-fortran-code/#Struct-Type-Correspondences-1

  2. Dealing with complex C structure [discurse.julialang] https://discourse.julialang.org/t/dealing-with-complex-c-structure/9045

  3. Potential wrong alignments and sizes of structs with C Unions https://github.com/JuliaInterop/Clang.jl/issues/238

  4. Structure padding and packing https://stackoverflow.com/questions/4306186/structure-padding-and-packing

  5. Using C Libraries from Julia (interesting blog post from Cbinding.jl developer) https://www.analytech-solutions.com/analytech-solutions/blog/cbinding.html

In general, we and these links are in the same direction. But i need a deepest read.

In addition 2 interesting resources to perform alternative implementations:

  1. Use unsafe_convert/unsafe_load instead of reinterpret https://github.com/JuliaMultimedia/CSFML.jl/blob/812f21224d683f4119b02c456dda47d4d0a4a471/src/Window/window_common.jl#L272-L314

  2. Improvements for specifying and using C bindings in Julia [CBinding.jl] https://github.com/analytech-solutions/CBinding.jl

krrutkow commented 4 years ago

There is also https://github.com/analytech-solutions/CBindingGen.jl you should check out. It is still somewhat WIP, but would give you another option.

amartinhuertas commented 4 years ago

There is also https://github.com/analytech-solutions/CBindingGen.jl you should check out. It is still somewhat WIP, but would give you another option.

Thanks @krrutkow !!! We will certainly take a look at it.