8.6.2 Ambiguous conditions

attempting to position a file outside its boundaries:

REPOSITION-FILE is performed as usual: Afterwards, FILE-POSITION returns the value given to REPOSITION-FILE.

attempting to read from file positions not yet written:

End-of-file, i.e., zero characters are read and no error is reported.

file-id is invalid (INCLUDE-FILE):

An appropriate exception may be thrown, but a memory fault or other problem is more probable.

I/O exception reading or closing file-id (INCLUDE-FILE, INCLUDED):

The ior produced by the operation, that discovered the problem, is thrown.

named file cannot be opened (INCLUDED):

The ior produced by open-file is thrown.

requesting an unmapped block number:

There are no unmapped legal block numbers. On some operating systems, writing a block with a large number may overflow the file system and have an error message as consequence.

using source-id when blk is non-zero:

source-id performs its function. Typically it will give the id of the source which loaded the block. (Better ideas?)