diff --git a/libmei/addons/att.h b/libmei/addons/att.h
index 5ce5886d4b..17f71d0aa2 100644
--- a/libmei/addons/att.h
+++ b/libmei/addons/att.h
@@ -90,8 +90,8 @@ class Att : public AttConverterBase {
     std::string MeasurementsignedToStr(data_MEASUREMENTSIGNED data) const;
     data_MEASUREMENTSIGNED StrToMeasurementsigned(const std::string &value, bool logWarning = true) const;
 
-    std::string MeasurementunsignedToStr(data_MEASUREMENTUNSIGNED data) const { return MeasurementsignedToStr(data); }
-    data_MEASUREMENTUNSIGNED StrToMeasurementunsigned(const std::string &value, bool logWarning = true) const
+    inline std::string MeasurementunsignedToStr(data_MEASUREMENTUNSIGNED data) const { return MeasurementsignedToStr(data); }
+    inline data_MEASUREMENTUNSIGNED StrToMeasurementunsigned(const std::string &value, bool logWarning = true) const
     {
         return StrToMeasurementsigned(value, logWarning);
     }
@@ -105,23 +105,23 @@ class Att : public AttConverterBase {
     std::string ModusminorToStr(data_MODUSMINOR data) const;
     data_MODUSMINOR StrToModusminor(const std::string &value, bool logWarning = true) const;
 
-    std::string MidibpmToStr(data_MIDIBPM data) const { return IntToStr(data); }
-    data_MIDIBPM StrToMidibpm(const std::string &value) const { return StrToInt(value); }
+    inline std::string MidibpmToStr(data_MIDIBPM data) const { return IntToStr(data); }
+    inline data_MIDIBPM StrToMidibpm(const std::string &value) const { return StrToInt(value); }
 
-    std::string MidichannelToStr(data_MIDICHANNEL data) const { return IntToStr(data); }
-    data_MIDICHANNEL StrToMidichannel(const std::string &value) const { return StrToInt(value); }
+    inline std::string MidichannelToStr(data_MIDICHANNEL data) const { return IntToStr(data); }
+    inline data_MIDICHANNEL StrToMidichannel(const std::string &value) const { return StrToInt(value); }
 
-    std::string MidimspbToStr(data_MIDIMSPB data) const { return IntToStr(data); }
-    data_MIDIMSPB StrToMidimspb(const std::string &value) const { return StrToInt(value); }
+    inline std::string MidimspbToStr(data_MIDIMSPB data) const { return IntToStr(data); }
+    inline data_MIDIMSPB StrToMidimspb(const std::string &value) const { return StrToInt(value); }
 
-    std::string MidivalueToStr(data_MIDIVALUE data) const { return IntToStr(data); }
-    data_MIDIVALUE StrToMidivalue(const std::string &value) const { return StrToInt(value); }
+    inline std::string MidivalueToStr(data_MIDIVALUE data) const { return IntToStr(data); }
+    inline data_MIDIVALUE StrToMidivalue(const std::string &value) const { return StrToInt(value); }
 
-    std::string NcnameToStr(data_NCNAME data) const { return StrToStr(data); }
-    data_NCNAME StrToNcname(const std::string &value) const { return StrToStr(value); }
+    inline std::string NcnameToStr(data_NCNAME data) const { return StrToStr(data); }
+    inline data_NCNAME StrToNcname(const std::string &value) const { return StrToStr(value); }
 
-    std::string OctaveToStr(data_OCTAVE data) const { return IntToStr(data); }
-    data_OCTAVE StrToOctave(const std::string &value) const { return StrToInt(value); }
+    inline std::string OctaveToStr(data_OCTAVE data) const { return IntToStr(data); }
+    inline data_OCTAVE StrToOctave(const std::string &value) const { return StrToInt(value); }
 
     std::string OctaveDisToStr(data_OCTAVE_DIS data) const;
     data_OCTAVE_DIS StrToOctaveDis(const std::string &value, bool logWarning = true) const;