CHARACTER_STORAGE_SIZE		Size of a character in bits.
ERROR_UNIT		Unit number for standard error.
FILE_STORAGE_SIZE		Size of the file storage unit in bits.
INPUT_UNIT		Unit number for standard input.
IOSTAT_END		Value assigned to IOSTAT variables at end-of-file.
IOSTAT_EOR		Value assigned to IOSTAT variables at end-of-record.
NUMERIC_STORAGE_SIZE		Size of the numeric storage unit in bits.
OUTPUT_UNIT		Unit number for standard output.
