Returns #t if v is an input port, #f otherwise.

Returns #t if v is an output port, #f otherwise.

Returns #t if either (input-port? v) or (output-port? v) is #t, #f otherwise.

Closes the input port in. For some kinds of ports, closing the port releases lower-level resources, such as a file handle. If the port is already closed, close-input-port has no effect.

Closes the output port out. For some kinds of ports, closing the port releases lower-level resources, such as a file handle. Also, if the port is buffered, closing may first flush the port before closing it, and this flushing process can block. If the port is already closed, close-output-port has no effect.

Returns #t if the input or output port port is closed, #f otherwise.

A parameter that determines a default input port for many operations, such as read.

A parameter that determines a default output port for many operations, such as write.

A parameter that determines an output port that is typically used for errors and logging. For example, the default error display handler writes to this port.

Returns #t if the given port is a file-stream port (see File Ports), #f otherwise.

Returns #t if the given port is attached to an interactive terminal, #f otherwise.

A value (distinct from all other values) that represents an end-of-file.

Returns #t if v is eof, #f otherwise.