When READ is used to read data from sequential unformatted files, the following specifiers are associated with the statement:
<value> specifies the unit number. The keyword and equals sign are optional if it is the first item in the specifier list.
<variable> will contain zero if the operation was successful, otherwise a positive value to indicate an error, -1 to indicate EOF or -2 to indicate EOR.
<label> specifies a label to go to in the event of an error.
<label> specifies a label to go to on end of file.