Issues with unicode characters in filenames on Windows 10 (Unix-like situation is currently unknown to me).

[thalassocracy]

https://github.com/JuliaAudio/LibSndFile.jl/blob/master/src/libsndfile_h.jl#L122

function sf_open(fname::String, mode, sfinfo)
    filePtr = ccall((:sf_open, libsndfile), Ptr{Cvoid},
                    (Cstring, Int32, Ref{SF_INFO}),
                    fname, mode, sfinfo)

    if filePtr == C_NULL
        error("LibSndFile.jl error while opening $fname: ", sf_strerror(C_NULL))
    end

    filePtr
end

Fixed on Windows 10 by changing Cstring to Cwstring and sf_open to sf_wchar_open.

The sf_wchar_open change is definitely Windows-specific, but there's a chance that opening filenames with wide characters in them on Unix-like systems will also benefit from changing Cstring to Cwstring. I will experiment with this at some point in the near future on Linux.

If I find that Linux also requires Cwstring, I will open a pull req with that change (but not the Windows-specific sf_wchar_open).

[nantonel]

I partially fixed the problem in Julia 1.6 using the following:

  if Sys.iswindows()
    ptr = pointer(transcode(Cwchar_t,fname))
    filePtr = ccall((:sf_wchar_open, libsndfile), Ptr{Cvoid},
                    (Cwstring, Int32, Ref{SF_INFO}),
                    Cwstring(ptr), mode, sfinfo)
  else
    filePtr = ccall((:sf_open, libsndfile), Ptr{Cvoid},
                    (Cstring, Int32, Ref{SF_INFO}),
                    fname, mode, sfinfo)
  end

however some tests are randomly breaking with the message The filename, directory name, or volume label syntax is incorrect.. This seems to be a Windows string encoding problem. Possibly it'll be fixed in newer Julia versions.