diff --git a/minimal_heap.h b/minimal_heap.h
index 8ba549d..c8a04a4 100644
--- a/minimal_heap.h
+++ b/minimal_heap.h
@@ -210,7 +210,7 @@ size_t MIHP_GetMinimalPayloadSize(const MIHP_Heap* heap);
 size_t MIHP_GetMaximalPayloadSize(const MIHP_Heap* heap);
 /* */
 
-#if MIHP_IMPLEMENTATION
+#ifdef MIHP_IMPLEMENTATION
 	#include "minimal_heap_implementation.inl"
 #endif
 
diff --git a/minimal_heap_test.cpp b/minimal_heap_test.cpp
index d526aeb..50737fe 100644
--- a/minimal_heap_test.cpp
+++ b/minimal_heap_test.cpp
@@ -1,4 +1,4 @@
-#define MIHP_IMPLEMENTATION 1
+#define MIHP_IMPLEMENTATION
 #include "minimal_heap.h"
 
 #include <stdlib.h>