Arduino C++ include error detected

Hello, I’ve initialized new project for my Arduino board where I’m using c++17, the application is working except I can’t include any of these:
#include <iostream>
#include <string>

I’m getting “include error detected, update your includePath” message.

Here is my platformio.ini file

platform = atmelavr
framework = arduino
board = uno
lib_deps = uipethernet/UIPEthernet@^2.0.8
build_unflags = -std=gnu++11
build_flags = -std=c++17

Correct. These don’t exist in the very limited AVR-GCC implementation.

Duplicate of Arduino c++11 or c++14 support in platform IO - #3 by maxgerhardt, see ArduinoSTL if you want a replacement for that missing header.