diff --git a/Source/MIKMIDIInputPort.h b/Source/MIKMIDIInputPort.h
index 9a770c4e..a2d31340 100644
--- a/Source/MIKMIDIInputPort.h
+++ b/Source/MIKMIDIInputPort.h
@@ -7,16 +7,14 @@
 //
 
 #import "MIKMIDIPort.h"
+#import "MIKMIDISourceEndpoint.h"
 #import "MIKMIDICompilerCompatibility.h"
 
 @class MIKMIDIEndpoint;
-@class MIKMIDISourceEndpoint;
 @class MIKMIDICommand;
 
 NS_ASSUME_NONNULL_BEGIN
 
-typedef void(^MIKMIDIEventHandlerBlock)(MIKMIDISourceEndpoint *source, MIKArrayOf(MIKMIDICommand *) *commands); // commands in an array of MIKMIDICommands
-
 /**
  *  MIKMIDIInputPort is an Objective-C wrapper for CoreMIDI's MIDIPort class, and is only for source ports.
  *  It is not intended for use by clients/users of of MIKMIDI. Rather, it should be thought of as an
diff --git a/Source/MIKMIDISourceEndpoint.h b/Source/MIKMIDISourceEndpoint.h
index cdb8a804..6a0027e5 100644
--- a/Source/MIKMIDISourceEndpoint.h
+++ b/Source/MIKMIDISourceEndpoint.h
@@ -7,6 +7,20 @@
 //
 
 #import "MIKMIDIEndpoint.h"
+#import "MIKMIDICompilerCompatibility.h"
+
+@class MIKMIDISourceEndpoint;
+@class MIKMIDICommand;
+
+NS_ASSUME_NONNULL_BEGIN
+
+/**
+ *  Block used by various MIKMIDI APIs that deliver incoming MIDI messages.
+ *
+ *  @param source	The source endpoint from which MIDI messagse were received.
+ *  @param commands	An NSArray containing received MIKMIDICommand instances.
+ */
+typedef void(^MIKMIDIEventHandlerBlock)(MIKMIDISourceEndpoint *source, MIKArrayOf(MIKMIDICommand *) *commands); // commands in an array of MIKMIDICommands
 
 /**
  *  MIKMIDISourceEndpoint represents a source (input) MIDI endpoint.
@@ -26,3 +40,5 @@
 @interface MIKMIDISourceEndpoint : MIKMIDIEndpoint
 
 @end
+
+NS_ASSUME_NONNULL_END
\ No newline at end of file