diff --git a/include/cb.h b/include/cb.h
index e536f99..9852bb8 100644
--- a/include/cb.h
+++ b/include/cb.h
@@ -8,11 +8,13 @@
 
 #define assertm(exp, msg) = assert(((void)msg, exp))
 
-#define or ||
-#define and &&
-#define xor ^
-#define compl ~
-#define not !
+#ifndef or
+    #define or ||
+    #define and &&
+    #define xor ^
+    #define compl ~
+    #define not !
+#endif
 
 #endif