Binary (COMP) items
BINARY, COMP, and COMP-4 are synonyms on all platforms.
Binary format numbers occupy 2, 4, or 8 bytes of storage. If the picture clause specifies that the item is signed, the leftmost bit is used as the operational sign.
A binary number with a PICTURE description of four or fewer decimal digits occupies 2 bytes; five to nine decimal digits, 4 bytes; and 10 to 18 decimal digits, 8 bytes. Binary items with nine or more digits require more handling by the compiler. Testing them for the SIZE ERROR condition and rounding is more cumbersome than with other types.
You can use binary items, for example, for indexes, subscripts, switches, and arithmetic operands or results.
Use the TRUNC(STD|OPT|BIN) compiler option to indicate how binary data (BINARY, COMP, or COMP-4) is to be truncated.