diff --git a/VkCppGenerator.cpp b/VkCppGenerator.cpp
index 7acb72c..cf51cc2 100644
--- a/VkCppGenerator.cpp
+++ b/VkCppGenerator.cpp
@@ -224,7 +224,7 @@ std::string const optionalClassHeader = (
   "\n"
   "    operator RefType*() const { return m_ptr; }\n"
   "    RefType const* operator->() const { return m_ptr; }\n"
-  "    explicit operator bool() const { return !m_ptr; }\n"
+  "    explicit operator bool() const { return !!m_ptr; }\n"
   "\n"
   "  private:\n"
   "    RefType *m_ptr;\n"
diff --git a/vulkan/vk_cpp.h b/vulkan/vk_cpp.h
index fb437f3..16b4d56 100644
--- a/vulkan/vk_cpp.h
+++ b/vulkan/vk_cpp.h
@@ -193,7 +193,7 @@ namespace vk
 
     operator RefType*() const { return m_ptr; }
     RefType const* operator->() const { return m_ptr; }
-    explicit operator bool() const { return !m_ptr; }
+    explicit operator bool() const { return !!m_ptr; }
 
   private:
     RefType *m_ptr;