Remove c-addr u from the stack. Save the current input source specification, including the current value of SOURCE-ID. Open the file specified by c-addr u, store the resulting fileid in SOURCE-ID, and make it the input source. Store zero in BLK. Other stack effects are due to the words included.

Repeat until end of file: read a line from the file, fill the input buffer from the contents of that line, set >IN to zero, and interpret.

Text interpretation begins at the start of the file.

When the end of the file is reached, close the file and restore the input source specification to its saved value.

An ambiguous condition exists if the named file can not be opened, if an I/O exception occurs reading the file, or if an I/O exception occurs while closing the file. When an ambiguous condition exists, the status (open or closed) of any files that were being interpreted is implementation-defined.

INCLUDED may allocate memory in data space before it starts interpreting the file.