diff --git a/include/ifax/types.h b/include/ifax/types.h
index 5ad819d..07c2cf0 100644
--- a/include/ifax/types.h
+++ b/include/ifax/types.h
@@ -6,14 +6,19 @@
 /* FIXME - We should autoconf that !
  */
 
+#ifndef _IFAX_TYPES_H
+#define _IFAX_TYPES_H
+
 typedef unsigned char ifax_uint8;
-typedef signed   char ifax_int8;
+typedef signed   char ifax_sint8;
+typedef          char ifax_int8;
 
 typedef unsigned short ifax_uint16;
-typedef short ifax_int16;
+typedef signed   short ifax_sint16;
+typedef          short ifax_int16;
 
 typedef unsigned int ifax_uint32;
-typedef int ifax_int32;
+typedef signed   int ifax_sint32;
+typedef          int ifax_int32;
 
-//typedef unsigned long long ifax_uint64;
-//typedef long long ifax_int64;
+#endif