Function preadv2 

pub fn preadv2<Fd: AsFd>(
    fd: Fd,
    bufs: &mut [IoSliceMut<'_>],
    offset: u64,
    flags: ReadWriteFlags,
) -> Result<usize>

preadv2(fd, bufs, offset, flags)—Reads data, with several options.

An offset of u64::MAX means to use and update the current file offset.

References

• Linux
• glibc