Duplicates a File handle.
This operation does not duplicate the actual file or directory represented by the File; see copy if attempting to copy a file.
dup is useful when a second handle is needed to the same underlying file, for use in a separate thread (File is not thread-safe). For use within the same thread, use @ref to increment the existing object’s reference count.
This call does no blocking I/O.
this |
input File |