The module Foreign.Marshal re-exports the other modules in the Foreign.Marshal hierarchy:
module Foreign.Marshal.Alloc |
module Foreign.Marshal.Array |
module Foreign.Marshal.Error |
module Foreign.Marshal.Utils |
and provides one function:
unsafeLocalState :: IO a -> a |
The only IO operations allowed in the IO action passed to unsafeLocalState are (a) local allocation (alloca, allocaBytes and derived operations such as withArray and withCString), and (b) pointer operations (Foreign.Storable and Foreign.Ptr) on the pointers to local storage, and (c) foreign functions whose only observable effect is to read and/or write the locally allocated memory. Passing an IO operation that does not obey these rules results in undefined behaviour.
It is expected that this operation will be replaced in a future revision of Haskell.