unlink vs remove in c++

remove is portable, and unlink is Unix-specific. :-P

Apart from the fact that unlink is unix-specific (as pointed out by Chris), we read in the POSIX manual:

If path does not name a directory, remove(path) is equivalent to unlink(path). If path names a directory, remove(path) is equivalent to rmdir(path).

As for the directory-passed unlink, we read:

The path argument must not name a directory unless the process has appropriate privileges and the implementation supports using unlink() on directories. (...) Applications should use rmdir() to remove a directory.