Compile error with MAC os

While trying to compile my project in MAC with xcode, there’s an error that I can’t figure out.

This error happens when I’m trying to use shared_timed_mutex

the compiler giave me this error: shared_timed_mutex’ is unavailable: introduced in macos 10.12
, but my target OS was set to 10.13

however when I open a C++ project for testing(not ue4 C++, just a hello world project) and use shared_timed_mutex, it compiled without any issue, I wonder if there’s any setting that I need to do for the project?

this link saves me