A canonical() function has been added at the suggest of David Svoboda from CERT. Boost.Filesystem's class path had such a function at one time, but it was deprecated because it didn't handle symlinks correctly. The new canonical() free function walks the path resolving symlinks, so now works correctly even when symlinks are present. For the curious, David's rationale for the function follows. --Beman Canonicalized pathnames are an important security measure when you want to do validity checking on your path (eg does this path live in /home/goodguy or /home/badguy?). There are several implementations of canonicalization functions, ranging from POSIX's realpath() function, to the GNU library's canonicalize_file_name(). For platform-independent implementations, Java provides the File.getCanonicalFile() method. CERT advocates the use of canonicalized filenames in its Secure Coding rules for both C FIO02-C. Canonicalize path names originating from untrusted sources https://www.securecoding.cert.org/confluence/x/EAY and Java IDS02-J. Canonicalize path names before validating them https://www.securecoding.cert.org/confluence/x/S4EVAQ