base-3.0.2.0: Basic libraries Source code Contents Index

Foreign.Concurrent Portability non-portable (requires concurrency) Stability provisional Maintainer ffi@haskell.org

Contents Concurrency-based ForeignPtr operations

Description

FFI datatypes and operations that use or require concurrency (GHC only).

Synopsis

newForeignPtr :: Ptr a -> IO () -> IO (ForeignPtr a) addForeignPtrFinalizer :: ForeignPtr a -> IO () -> IO ()

Concurrency-based ForeignPtr operations

These functions generalize their namesakes in the portable Foreign.ForeignPtr module by allowing arbitrary IO actions as finalizers. These finalizers necessarily run in a separate thread, cf. Destructors, Finalizers and Synchronization, by Hans Boehm, POPL, 2003.

newForeignPtr :: Ptr a -> IO () -> IO (ForeignPtr a) Source

Turns a plain memory reference into a foreign object by associating a finalizer - given by the monadic operation - with the reference. The finalizer will be executed after the last reference to the foreign object is dropped. Note that there is no guarantee on how soon the finalizer is executed after the last reference was dropped; this depends on the details of the Haskell storage manager. The only guarantee is that the finalizer runs before the program terminates.

addForeignPtrFinalizer :: ForeignPtr a -> IO () -> IO () Source

This function adds a finalizer to the given ForeignPtr. The finalizer will run after the last reference to the foreign object is dropped, but before all previously registered finalizers for the same object.

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