diff --git a/src/wrap_cl.hpp b/src/wrap_cl.hpp
index d31d16359e72accb8b91bec811363df5d3246a81..9e0b1edeeff19c2625466ee4abbcaa9159ed839f 100644
--- a/src/wrap_cl.hpp
+++ b/src/wrap_cl.hpp
@@ -3884,7 +3884,7 @@ namespace pyopencl
     PYOPENCL_GET_SVM_SIZE(src);
     PYOPENCL_GET_SVM_SIZE(dst);
 
-    size_t size;
+    size_t size = 0;
     bool have_size = false;
 
     if (src_has_size)
@@ -3965,7 +3965,7 @@ namespace pyopencl
 
     PYOPENCL_GET_SVM_SIZE(dst);
 
-    size_t size;
+    size_t size = 0;
     bool have_size = false;
     if (dst_has_size)
     {
@@ -4020,7 +4020,7 @@ namespace pyopencl
 
     PYOPENCL_GET_SVM_SIZE(svm);
 
-    size_t size;
+    size_t size = 0;
     bool have_size = false;
     if (svm_has_size)
     {