call to NativeMethods.fftwf_sprint_plan(handle); crashes

[siddjain]

Thanks a lot for this library. The call to NativeMethods.fftwf_sprint_plan(handle); crashes however. Any chance you could fix this?

[wo80]

Adding [return: MarshalAs(UnmanagedType.LPStr)] should do the trick, like

[return: MarshalAs(UnmanagedType.LPStr)]
public static extern string fftw_sprint_plan(IntPtr plan);

I'll update the code later today.

[siddjain]

Great! Thank you for fixing it so quickly.

[siddjain]

unfortunately it still crashes with this change! try it!

[wo80]

I tested it before committing the fix. It works for me. Which platform are you on, which FFTW dll are you using?

Could you - just for testing purpose - change the method to return an IntPtr to see if the call works?

[DllImport(Library, EntryPoint = "fftw_sprint_plan", ExactSpelling = true, CallingConvention = CallingConvention.Cdecl)]
public static extern IntPtr fftw_sprint_plan(IntPtr plan);

[siddjain]

I am on Windows x64. Using the precompiled dlls available on FFTW website. returning an IntPtr followed by Marshal.PtrToStringAnsi worked for me.

[siddjain]

https://stackoverflow.com/a/370519/147530

[wo80]

Alright, I'm using the recent FFTW 3.3.10 compiled with Visual Studio 2022. Marshal.PtrToStringAnsi works for me too, so I'll update the code to use that version.

[siddjain]

could you share the link to the binary? i can only find fftw-3.3.5-dll64 on official website.

[wo80]

There's a link in the readme, pointing to version 3.3.9 with only SSE2 enabled: http://wo80.bplaced.net/math/packages-fftw.html

I compiled my local version with AVX2 only, if I remember correctly. I'll upload it, if you are interested.

The CMake build script has it's pitfalls (SSE/AVX wasn't detected automatically for me), but it's not too hard to get it working, so you could also try to compile the code for yourself.

[siddjain]

thanks for the link and for making fftw accessible to C# developers!