diff --git a/TOOLS/avi-fix.c b/TOOLS/avi-fix.c
index 51376efc48..19aa55384a 100644
--- a/TOOLS/avi-fix.c
+++ b/TOOLS/avi-fix.c
@@ -15,7 +15,7 @@
 
 #define FCC(a,b,c,d)  (((a)<<24)|((b)<<16)|((c)<<8)|(d))
 
-static inline xx(unsigned char c){
+static inline char xx(unsigned char c){
     if(c>=32 && c<128) return c;
     return '?';
 }