Index: register.c
===================================================================
--- register.c	(revision 51)
+++ register.c	(revision 52)
@@ -23,7 +23,7 @@
 return -1;
 }
 
-char raydium_register_name_isvalid(char *name)
+signed char raydium_register_name_isvalid(char *name)
 {
 int i;
 for(i=0;i<strlen(name);i++)