Length modifier

The length modifier indicates the number of bytes of storage into which the constant is to be assembled. It is written as Ln, where n is either a decimal self-defining term or an absolute expression enclosed by parentheses. It must have a positive value.

When the length modifier is specified:

Its value determines the number of bytes of storage allocated to a constant. It therefore determines whether the nominal value of a constant must be padded or truncated to fit into the space allocated (see Padding and truncation of values).
No boundary alignment, according to constant type, is provided (see Alignment of constants).
Its value must not exceed the maximum length allowed for the various types of constant defined.
The length modifier must not truncate double-byte data in a C-type constant, except for bit-length modifiers.
The length modifier must be a multiple of 2 in a G-type or CU-type constant.

When no length is specified, for character and graphic constants (C and G), hexadecimal constants (X), binary constants (B), and decimal constants (P and Z), the whole constant is assembled into its implicit length.