|fd_copy(3)||Library Functions Manual||fd_copy(3)|
NAME¶fd_copy - duplicate a descriptor
DESCRIPTION¶fd_copy copies descriptor from to descriptor to. If to was already open, fd_copy closes it. fd_copy always leaves from intact; if to and from are the same number, fd_copy does nothing.
fd_copy returns 0 on success, -1 on error. fd_copy does not guarantee that to will remain open, if it was open, in case of error.