diff --git a/qmsgpack.pri b/qmsgpack.pri
index 1166d43..76039ee 100644
--- a/qmsgpack.pri
+++ b/qmsgpack.pri
@@ -1,5 +1,7 @@
 QT       += core location
 
+DEFINES += MSGPACK_MAKE_LIB
+
 INCLUDEPATH += $$PWD/src
 
 SOURCES += \