[ moved to glasgow-haskell-users ]

When I make a function generator with "foreign export dynamic", GHC spits out stub files which it apparently then needs for the link. What are these for?

The stub files contain the helper function which invokes the Haskell code when called from C. Each time the foreign export dynamic is invoked to create a new callback function, a small piece of code has to be dynamically generated. It is the address of this dynamically generated bit of code that is returned as the Addr (or Ptr). When called from C, the dynamically generated code must somehow invoke the Haskell function which was originally passed to the f.e.d. function - it does this by invoking the helper function, passing it a StablePtr to the Haskell function. It's split this way for two reasons: the same helper function can be used each time the f.e.d. function is called, and to keep the amount of dynamically generated code to a minimum. Cheers, Simon