extra memory copy?

[luanshaotong]

I am confused why there is no data buffer in parameters of read(). Does this mean that there is an extra memory copy when reading?

fuser/src/lib.rs

Line 494 in e01307c

fn read(

fuser/examples/simple.rs

Line 1397 in e01307c

let mut buffer = vec![0; read_size as usize];

[cberner]

I didn't write that code (it was there before I forked fuse into fuser), so I'm not entirely sure. However, no I don't think there is an unnecessary copy, if you trace the reply method you'll find that it bottoms out in a write to the file descriptor that goes back to the kernel

[luanshaotong]

@cberner Thank you for your answer, I didn't figure it out before, this is indeed a feature(or shortcoming?) of fuse.