path absolute(const path& p);
path absolute(const path& p, error_code& ec);
Effects: Composes an absolute path referencing the same file system location as p according to the operating system ([fs.conform.os]).
Throws: As specified in [fs.err.report].
[ Note: To resolve symlinks, or perform other sanitization which might require queries to secondary storage, such as hard disks, consider canonical ([fs.op.canonical]). — end note ]
[ Note: Implementations are strongly encouraged to not query secondary storage, and not consider !exists(p) an error. — end note ]