A variable to be bound to the foreign pointer.
A variable to be bound to the length in bytes.
Forms to be executed.
with-integer-bytes evaluates the forms in body with pointer bound to a dynamic foreign object containing the bytes of integer and length bound to the number of bytes in that object. The layout of the bytes is unspecified, but the bytes and the length are sufficient to reconstruct integer by calling make-integer-from-bytes.
LispWorks Foreign Language Interface User Guide and Reference Manual - 29 Sep 2017