Symbol: F_DUP3FD
lib/libc/gen/dup3.c
57
return (_fcntl(oldfd, F_DUP3FD | (fdflags << F_DUP3FD_SHIFT), newfd));
sys/kern/kern_descrip.c
1016
if ((cmd & ((1u << F_DUP3FD_SHIFT) - 1)) != F_DUP3FD)