1 files changed, 6 insertions, 6 deletions
diff --git a/src/audioinputenginemidi.h b/src/audioinputenginemidi.h
index 3f96afe..b892750 100644
--- a/src/audioinputenginemidi.h
+++ b/src/audioinputenginemidi.h
@@ -41,11 +41,11 @@ public:
   AudioInputEngineMidi();
   virtual ~AudioInputEngineMidi() {}
 
-  bool isMidiEngine() { return true; } 
+  bool isMidiEngine() const { return true; } 
 
-  virtual bool init(Instruments &instruments) = 0;
+  virtual bool init(const Instruments &instruments) = 0;
 
-  virtual void setParm(std::string parm, std::string value) = 0;
+  virtual void setParm(const std::string& parm, const std::string& value) = 0;
 
   virtual bool start() = 0;
   virtual void stop() = 0;
@@ -54,11 +54,11 @@ public:
   virtual void run(size_t pos, size_t len, std::vector<event_t>& events) = 0;
   virtual void post() = 0;
 
-  bool loadMidiMap(std::string file, Instruments &i);
+  bool loadMidiMap(const std::string& file, const Instruments& i);
 
-  std::string midimapFile();
+  std::string getMidimapFile() const;
 
-  bool isValid();
+  bool isValid() const;
 
 protected:
   MidiMapper mmap;