working on win32 uwp! and libremidi update

include/libremidi/detail/ump_stream.hpp

@@ -1,5 +1,6 @@
 #pragma once
 #include <libremidi/cmidi2.hpp>
+#include <libremidi/error.hpp>
 
 #include <cinttypes>
 #include <cstdint>
@@ -17,7 +18,7 @@ enum class segmentation_error
  * Utility function to segment an ump stream into individual messages.
  * Used to send a stream to APIs that work message-by-message.
  */
-inline void
+inline stdx::error
 segment_ump_stream(const uint32_t* ump_stream, int64_t count, auto write_func, auto realloc_func)
 {
   while (count > 0)
@@ -35,24 +36,27 @@ segment_ump_stream(const uint32_t* ump_stream, int64_t count, auto write_func, a
     const auto ump_bytes = cmidi2_ump_get_num_bytes(ump_stream[0]);
 
     // FIXME std::expected, propagate the error back to caller?
-    switch (write_func(ump_stream, ump_bytes))
+    switch (int err = static_cast<int>(write_func(ump_stream, ump_bytes)))
     {
-      case segmentation_error::no_error:
+      case 0:
         break;
-      case segmentation_error::need_space:
+      case -ENOMEM:
+      case ENOMEM:
         // Try again if we didn't have enough space in the OS queue
         realloc_func();
-        if (write_func(ump_stream, ump_bytes) != segmentation_error::no_error)
-          return;
+        if (auto err = write_func(ump_stream, ump_bytes); err != std::errc{})
+          return std::make_error_code(err);
         break;
-      case segmentation_error::other:
-        return;
+      default:
+        return from_errc(err);
     }
 
     const auto ump_uints = ump_bytes / 4;
     ump_stream += ump_uints;
     count -= ump_uints;
   }
+
+  return stdx::error{};
 }
 
 }