What I mean is a list of the standards used in paths, like for example:

Code:
%VAR%
$V
$(VAR)
Designing a pseudo file system for my cross-platform ABI so that reliant software can reduce the amount of work involved in path usage, for example pawfs://~ will always mean $(HOME) or %USERPROFILE% etc but it should also be valid to do something like this call:

Code:
#define PATH u8"$(HOME)/../.."
pawfs__envpathn( dst, max, PATH, pawmbslen(PATH), pawfs_env_shell_ptr, 1 );
Which will either fail (because HOME didn't exist) or produce "/home/user/../.." and I want to be able to produce a function that can validate a path based on what is allowed every supported OS and fail if it's not.