Might help to update the samples.

Author: Kraust

samples/server/petstore/cpp-oatpp/CMakeLists.txt

@@ -2,7 +2,7 @@ cmake_minimum_required (VERSION 3.2)
 
 project(api-server)
 
-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -pg -g3" )
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++17 -pg -g3" )
 
 include(ExternalProject)