diff --git a/demos/cube.c b/demos/cube.c
index cd1ccaa..74478f8 100644
--- a/demos/cube.c
+++ b/demos/cube.c
@@ -451,7 +451,7 @@
         .flags = 0,
     };
     XGL_MEMORY_REQUIREMENTS mem_reqs;
-    XGL_SIZE mem_reqs_size;
+    XGL_SIZE mem_reqs_size = sizeof(XGL_MEMORY_REQUIREMENTS);
     XGL_RESULT err;
 
     demo->depth.format = depth_format;
@@ -701,7 +701,7 @@
             .minLod = 0.0f,
         };
         XGL_MEMORY_REQUIREMENTS mem_reqs;
-        XGL_SIZE mem_reqs_size;
+        XGL_SIZE mem_reqs_size = sizeof(XGL_MEMORY_REQUIREMENTS);
 
         /* create sampler */
         err = xglCreateSampler(demo->device, &sampler,
diff --git a/demos/tri.c b/demos/tri.c
index b6b6bdc..45bc4a9 100644
--- a/demos/tri.c
+++ b/demos/tri.c
@@ -243,7 +243,7 @@
         .flags = 0,
     };
     XGL_MEMORY_REQUIREMENTS mem_reqs;
-    XGL_SIZE mem_reqs_size;
+    XGL_SIZE mem_reqs_size= sizeof(XGL_MEMORY_REQUIREMENTS);
     XGL_RESULT err;
 
     demo->depth.format = depth_format;
@@ -345,7 +345,7 @@
             .minLod = 0.0f,
         };
         XGL_MEMORY_REQUIREMENTS mem_reqs;
-        XGL_SIZE mem_reqs_size;
+        XGL_SIZE mem_reqs_size= sizeof(XGL_MEMORY_REQUIREMENTS);
 
         /* create sampler */
         err = xglCreateSampler(demo->device, &sampler,