[clisp-list] Re: READ-SEQUENCE-ONCE

[Bruno H. <ha...@il...>]

Sam writes:

> > If you rename them to READ-CHAR-SEQUENCE-NONBLOCKING and
> > READ-BYTE-SEQUENCE-NONBLOCKING it's easier to understand what they do.
> 
> But they are _not_ non-blocking!
> they call read/write just once, and if that blocks, they do too.

This is not a well-defined description of some semantics, because a
single read() on a BSD system is not the same thing as a single read()
on a SysV system. On SysV, read() can return with a "short read"
spuriously, i.e. it can fill into the buffer fewer bytes than are
actually available - for no visible reason. Whereas on BSD systems,
your READ-BYTE-SEQUENCE-ONCE function will behave just like
READ-BYTE-SEQUENCE.

It's useless to introduce such variants if you cannot describe
in a portable way how they behave.

Bruno