Using __MAC_OS_X_VERSION_MIN_REQUIRED the header the decision to use std::filesystem or ghc::filesystem can correctly allow use of std::filesystem when deployment target is Catalina or newer, as the __cplusplus and header test are not enough to detect pre-Catalina conditions.
Using
__MAC_OS_X_VERSION_MIN_REQUIREDthe header the decision to use std::filesystem or ghc::filesystem can correctly allow use of std::filesystem when deployment target is Catalina or newer, as the __cplusplus and header test are not enough to detect pre-Catalina conditions.