diff --git a/src/sigar_cache.c b/src/sigar_cache.c
index 0dc6181c..c0cc8008 100644
--- a/src/sigar_cache.c
+++ b/src/sigar_cache.c
@@ -73,7 +73,7 @@ void sigar_cache_destroy(sigar_cache_t *table)
             if (ptr->value) {
                 free(ptr->value);
             }
-        } while (ptr = ptr->next);
+        } while ((ptr = ptr->next));
         free(entry);
     }