diff --git a/include/memory.h b/include/memory.h
index 6953970..37f7d39 100644
--- a/include/memory.h
+++ b/include/memory.h
@@ -147,7 +147,7 @@ struct st_r3_buffer_prototype_t {
 
 typedef R3_VECTOR(void) r3_vector_t;
 
-extern void *(*r3_mem__set_secure)(void *, int, unsigned int);
+extern void *(*r3_mem__set_secure)(void *, int, size_t);
 
 /**
  * prints an error message and aborts
diff --git a/src/memory.c b/src/memory.c
index bd4e873..d113e93 100644
--- a/src/memory.c
+++ b/src/memory.c
@@ -55,7 +55,7 @@ struct st_r3_mem_pool_shared_ref_t {
     struct st_r3_mem_pool_shared_entry_t *entry;
 };
 
-void *(*r3_mem__set_secure)(void *, int, unsigned int) = memset;
+void *(*r3_mem__set_secure)(void *, int, size_t) = memset;
 
 static __thread r3_mem_recycle_t mempool_allocator = {16};