Interpolation using $ with @cfunction in a macro reported as a closure, thus won't work on Apple Silicon

General Usage
2

The ArchGDAL.jl package is apparently using this for the GDALProgressFunc callback API.

It seems like the solution is to change the Julia package to use the void* argument (pProgressArg) to pass the closure argument, rather than forcing Julia to compile a new callback for every progressfunc argument it wants to handle (which apparently isn’t supported on M1). That is, they should define something like:

function progressfunc_wrapper(dfComplete::Cdouble, pszMessage::Ptr{UInt8}, pProgressArg::Any)::Cint
    pszMessage == C_NULL && return pProgressArg(dfComplete)
    return pProgressArg(dfComplete, unsafe_string(pszMessage))
end
const progressfunc_wrapper_c = @cfunction(progressfunc_wrapper, Cint, (Cdouble, Cstring, Any))

and then, any place you actually want to pass a progressfunc, you instead pass progressfunc_wrapper_c as the callback function and progressfunc as the callback-data argument.

In APIs that support a callback-data argument, like this one, the above is the approach I would recommend. It puts a lot fewer demands on the compiler.

(Also, then their progresscallback functions are simpler and more Julian. They are passed a Julia String as their optional “message” argument rather than a pointer, and can return true or false instead of a Cint, since progressfunc_wrapper handles the conversions.)

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