very, very simple WP with midi CC out

include/libremidi/backends/jack/config.hpp

@@ -0,0 +1,50 @@
+#pragma once
+#include <libremidi/config.hpp>
+
+#include <cinttypes>
+#include <cstdint>
+#include <functional>
+#include <string>
+
+extern "C" {
+typedef struct _jack_client jack_client_t;
+typedef uint32_t jack_nframes_t;
+typedef int (*JackProcessCallback)(jack_nframes_t nframes, void* arg);
+}
+
+namespace libremidi
+{
+using jack_callback_function = std::function<void(int nframes)>;
+struct jack_callback
+{
+  int64_t token;
+  std::function<void(int nframes)> callback;
+};
+struct jack_input_configuration
+{
+  std::string client_name = "libremidi client";
+
+  jack_client_t* context{};
+  std::function<void(jack_callback)> set_process_func;
+  std::function<void(int64_t)> clear_process_func;
+};
+
+struct jack_output_configuration
+{
+  std::string client_name = "libremidi client";
+
+  jack_client_t* context{};
+  std::function<void(jack_callback)> set_process_func;
+  std::function<void(int64_t)> clear_process_func;
+
+  int32_t ringbuffer_size = 16384;
+  bool direct = false;
+};
+
+struct jack_observer_configuration
+{
+  std::string client_name = "libremidi client";
+  jack_client_t* context{};
+};
+
+}