Execution of a BACKSPACE statement causes the disc file connected to the specified unit to be positioned before the preceding record. If there is no preceding record, the position of the file is unchanged. If the preceding record is an endfile record, the file is positioned before the endfile record.
You cannot backspace over a record that has been written using list-directed formatting.
The following specifiers are associated with the BACKSPACE statement:
<value> specifies the unit number. The keyword and equals sign are optional if this is the first item in the list. If unit number is the only argument, the brackets around the argument list are optional.
<variable> will contain zero if the operation was successful, otherwise a positive value to indicate an error.
<label> specifies a label to go to in the event of an error.