Exceptions in Input/Output

TEXT_IO defines several exceptions:

Exception	Example
DATA_ERROR	invalid data type, data has wrong form
STATUS_ERROR	try to open an already open file
MODE_ERROR	try to read from an output file
NAME_ERROR	no such file
USE_ERROR	try to open printer for reading
END_ERROR	EOF encountered while reading
LAYOUT_ERROR	SET_COL beyond LINELENGTH limit
DEVICE_ERROR	hardware failure

Several examples show how some of these exceptions may be handled during input/output:

• reading enumeration values
• reading enumeration values, with range checks
• reading float values, with range checks
• opening a file