File Ports

The following procedures are used to open file ports. See also section Ports and File Descriptors, for an interface to the Unix open system call.

primitive: open-file string mode

Open the file whose name is string, and return a port representing that file. Whether an input or output port is allocated is determined by the mode string. This is interpreted in the traditional Unix manner: use `r' for reading, `w' for writing, and `a' for appending. In addition, `0' can be used to specifiy an unbuffered port.

See the stdio documentation for your system for more I/O mode options.

If a file cannot be opened, open-file throws an exception.

procedure: open-input-file filename

Open filename for input. Equivalent to

(open-file filename "r")

procedure: open-output-file filename

Open filename for output. Equivalent to

(open-file filename "w")

primitive: port-mode port

Return the mode flags from the open port.

primitive: port-filename [port]

Return the filename associated with port. This function returns the strings "standard input", "standard output" and "standard error" when called on the current input, output and error ports respectively.

primitive: set-port-filename! [port] filename

Change the filename associated with port, using the current input port if none is specified. Note that this does not change the port's source of data, but only the value that is returned by port-filename and reported in diagnostic output.

primitive: %make-void-port mode

Create and return a new void port. The mode argument describes the permissions to use for this port; for a description, see the documentation for open-file in section File Ports.

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