A symbol naming a foreign block type defined using define-foreign-block-callable-type.
allocates a foreign block using
in the same way as allocate-foreign-block, but with dynamic extent. It then binds
to the foreign block and executes the code of
can be used only if the code in
can be guaranteed not to invoke the block or a copy of it either outside the scope of
or in another thread. Unless you can be sure of that, you need to use with-foreign-block.
can be a little faster than with-foreign-block.
LispWorks Foreign Language Interface User Guide and Reference Manual - 7 Dec 2011