How to have an array type in C binding?

Question

I'm trying to port this code :

struct SoundIoChannelLayout {
    const char *name;
    int channel_count;
    enum SoundIoChannelId channels[SOUNDIO_MAX_CHANNELS];
};

But i don't know how to define the type of channels, and I know that I can't use a pointer because the final struct size won't be the same.

Answer 1

I was able to auto-generate it using crystal_lib:

$ cd crystal_lib
$ cat examples/soundio.cr
@[Include("soundio/soundio.h", prefix: %w(SoundIo))]
@[Link("soundio")]
lib LibSoundio
end
$ crystal src/main.cr -- examples/soundio.cr > soundio.cr

So it looks like this:

@[Link("soundio")]
lib LibSoundio
  MAX_CHANNELS = 24

  struct ChannelLayout
    name : LibC::Char*
    channel_count : LibC::Int
    channels : ChannelId[MAX_CHANNELS]
  end

  enum ChannelId
    Invalid = 0
    FrontLeft = 1
    FrontRight = 2
    FrontCenter = 3
    # ...
  end
  # ...
end

Note: you may need to update resulted file manually because crystal_lib is still experimental.