diff --git a/src/wrap_mempool.cpp b/src/wrap_mempool.cpp
index cb711b1b27ea11645361665aa60ade6a9c687b20..46845594ec2c48a828bebdbba9f11d5a7cf27092 100644
--- a/src/wrap_mempool.cpp
+++ b/src/wrap_mempool.cpp
@@ -253,7 +253,7 @@ namespace pyopencl {
   inline
   buffer *allocate_from_buffer_allocator(buffer_allocator_base &alloc, size_t size)
   {
-    cl_mem mem;
+    cl_mem mem = nullptr;
     int try_count = 0;
     while (try_count < 2)
     {