diff --git a/base/VulkanTools.cpp b/base/VulkanTools.cpp
index f7cca5d9..c48da525 100644
--- a/base/VulkanTools.cpp
+++ b/base/VulkanTools.cpp
@@ -315,7 +315,7 @@ namespace vks
 			else
 			{
 				std::cerr << "Error: Could not open shader file \"" << fileName << "\"" << std::endl;
-				return nullptr;
+				return VK_NULL_HANDLE;
 			}
 		}
 #endif
diff --git a/base/vulkanexamplebase.cpp b/base/vulkanexamplebase.cpp
index 128e56a2..d5bf90eb 100644
--- a/base/vulkanexamplebase.cpp
+++ b/base/vulkanexamplebase.cpp
@@ -205,7 +205,7 @@ VkPipelineShaderStageCreateInfo VulkanExampleBase::loadShader(std::string fileNa
 	shaderStage.module = vks::tools::loadShader(fileName.c_str(), device, stage);
 #endif
 	shaderStage.pName = "main"; // todo : make param
-	assert(shaderStage.module != NULL);
+	assert(shaderStage.module != VK_NULL_HANDLE);
 	shaderModules.push_back(shaderStage.module);
 	return shaderStage;
 }