[akira2501]

> just never use pipes.

vmslice doesn't work with every type of file descriptor. eschewing some technology entirely because it seems archaic or because it makes writing "the fastest X software" seem harder is just sloppy engineering.

> they are just not useful.

Then you have not written enough software yet to discover how they are useful.

[gpderetta]

Most importantly the fast fizbuz toy vmsplices into /dev/null.

Nothing ever touches those pages on the consumer side and they can be refused immediately.

If you actually want a functional program using vmsplice, with a real consumer, things get hairy very quickly.