DLL thread safety

Hi, I'm building a DLL using the instructions here: http://www.haskell.org/ghc/docs/latest/html/users_guide/win32-dlls.html I must call startupHaskell before I make any calls to Haskell functions. However, that page doesn't detail any thread safety rules. In particular: * If I call startupHaskell on Thread 1, can I make Haskell calls from Thread 2. * Can I make Haskell calls from both Thread 1 and Thread 2 simultaneously. Many thanks Neil