2 files changed, 17 insertions, 2 deletions

diff --git a/src/allocator.c b/src/allocator.c
index d6aeea9..1627089 100644
--- a/src/allocator.c
+++ b/src/allocator.c
@@ -1,23 +1,31 @@
 #include "allocator.h"
 
+#include <assert.h>
 #include <stdlib.h> /* malloc */
 
+#ifndef UNUSED
+#       define UNUSED(var) (void) (var)
+#endif
+
 /* Interface Code */
 static void *
 default_allocate(struct allocator *allocator, size_t n)
 {
-        (void) allocator;
+        UNUSED(allocator);
         return malloc(n);
 }
 
 static void
 default_deallocate(struct allocator *allocator, void *ptr)
 {
-        (void) allocator;
+        UNUSED(allocator);
         free(ptr);
 }
 
 struct allocator allocator_default_allocator = {
+#ifndef NDEBUG
+        .self = &allocator_default_allocator,
+#endif
         .allocate   = &default_allocate,
         .deallocate = &default_deallocate
 };
@@ -32,6 +40,8 @@ allocator_malloc(struct allocator *allocator, size_t n)
                 allocator = &allocator_default_allocator;
         }
 
+        assert(allocator->self == allocator);
+
         return allocator->allocate(allocator, n);
 }
 
@@ -42,6 +52,8 @@ allocator_free(struct allocator *allocator, void *ptr)
                 allocator = &allocator_default_allocator;
         }
 
+        assert(allocator->self == allocator);
+
         allocator->deallocate(allocator, ptr);
 }
 
diff --git a/src/allocator.h b/src/allocator.h
index dd9bb16..2c0c5b9 100644
--- a/src/allocator.h
+++ b/src/allocator.h
@@ -3,6 +3,9 @@
 #include <stddef.h> /* size_t */
 
 struct allocator {
+#ifndef NDEBUG
+        struct allocator *self;
+#endif
         void *(*allocate)(struct allocator *allocator, size_t n);
         void (*deallocate)(struct allocator *allocator, void *ptr);
 };