diff --git a/libgy521.h b/libgy521.h
index ecdccb7..ef356d8 100644
--- a/libgy521.h
+++ b/libgy521.h
@@ -1,13 +1,13 @@
-int setupgy521(void);
-int read_i2c_word(int reg);
-int read_i2c_word16(int reg);
-float getTemp(void);
-void setAccelerometerRange(int range);
-int readAccelerometerRange(int raw);
-int getAccelerometerData(char axis, int g);
-void setGyroscopeRange(int range);
-int readGyroscopeRange(int raw);
-int getGyroscopeData(char axis);
-float getAngleX(void);
-float getAngleY(void);
-float getAngleZ(void);
+extern int setupgy521(void);
+extern int read_i2c_word(int reg);
+extern int read_i2c_word16(int reg);
+extern float getTemp(void);
+extern void setAccelerometerRange(int range);
+extern int readAccelerometerRange(int raw);
+extern int getAccelerometerData(char axis, int g);
+extern void setGyroscopeRange(int range);
+extern int readGyroscopeRange(int raw);
+extern int getGyroscopeData(char axis);
+extern float getAngleX(void);
+extern float getAngleY(void);
+extern float getAngleZ(void);
diff --git a/makefile b/makefile
index 842fa82..fcbad0a 100644
--- a/makefile
+++ b/makefile
@@ -1,20 +1,15 @@
-#Infos: http://www.ijon.de/comp/tutorials/makefile.html
-
-
 VERSION = 1.0
-CC      = /usr/bin/gcc
-CFLAGS  = -Wall -g -D_REENTRANT -DVERSION=\"$(VERSION)\" 
-#LDFLAGS = -lm -lpthread `gtk-config --cflags` `gtk-config --libs` -lgthread
+CFLAGS  = -Wall -g -D_REENTRANT -DVERSION=\"$(VERSION)\" -O3
 LDFLAGS = -lwiringPi -lm
 
-OBJ = gy521example.o libgy521.o
+all: lib test
 
-libgy521: $(OBJ)
-	$(CC) $(CFLAGS) -o gy521example $(OBJ) $(LDFLAGS)
-        
-%.o: %.c
-	$(CC) $(CFLAGS) -c $<
+lib: libgy521.o
+	cc -shared -o libgy521.so libgy521.o -lm -lwiringPi
 
+test: gy521example.o
+	cc -o test -L. gy521example.o -lgy521 -lwiringPi
+	
 .PHONY: clean
 clean:
 	rm -r *.o