Please note: For compatibility with DEC-10 Character I/O a set of predicates are provided, which are similar to the primary ones except that they always use the standard input and output streams, which normally refer to the user's terminal rather than to the current input stream or current output stream. They are easily recognizable as they all begin with tty.

Given stream-based input/output, these predicates are actually redundant. For example, you could write get0(user, C) instead of ttyget0(C).

This note applies to the character output as well (see ref-iou-cou).

The operations in this category are: