haskell-gi-base-0.15: Foundation for libraries generated by haskell-gi

Safe HaskellNone



Assorted utility functions for bindings.



whenJust :: Monad m => Maybe a -> (a -> m ()) -> m () Source

When the given value is of "Just a" form, execute the given action, otherwise do nothing.

maybeM :: Monad m => b -> Maybe a -> (a -> m b) -> m b Source

Like maybe, but for actions on a monad, and with slightly different argument order.

maybeFromPtr :: Ptr a -> Maybe (Ptr a) Source

Check if the pointer is nullPtr, and wrap it on a Maybe accordingly.

mapFirst :: (a -> c) -> [(a, b)] -> [(c, b)] Source

Given a function and a list of two-tuples, apply the function to every first element of the tuples.

mapFirstA :: Applicative f => (a -> f c) -> [(a, b)] -> f [(c, b)] Source

Applicative version of mapFirst.

mapSecond :: (b -> c) -> [(a, b)] -> [(a, c)] Source

Same for the second element.

mapSecondA :: Applicative f => (b -> f c) -> [(a, b)] -> f [(a, c)] Source

Applicative version of mapSecond.

convertIfNonNull :: Ptr a -> (Ptr a -> IO b) -> IO (Maybe b) Source

Apply the given conversion action to the given pointer if it is non-NULL, otherwise return Nothing.

callocBytes :: Int -> IO (Ptr a) Source

Make a zero-filled allocation using the GLib allocator.

callocBoxedBytes :: forall a. BoxedObject a => Int -> IO (Ptr a) Source

Make a zero filled allocation of n bytes for a boxed object. The difference with a normal callocBytes is that the returned memory is allocated using whatever memory allocator g_boxed_copy uses, which in particular may well be different from a plain g_malloc. In particular g_slice_alloc is often used for allocating boxed objects, which are then freed using g_slice_free.

callocMem :: forall a. Storable a => IO (Ptr a) Source

Make a zero-filled allocation of enough size to hold the given Storable type, using the GLib allocator.

allocBytes :: Integral a => a -> IO (Ptr b) Source

Allocate the given number of bytes using the GLib allocator.

allocMem :: forall a. Storable a => IO (Ptr a) Source

Allocate space for the given Storable using the GLib allocator.

freeMem :: Ptr a -> IO () Source

A wrapper for g_free.

ptr_to_g_free :: FunPtr (Ptr a -> IO ()) Source

Pointer to g_free.

memcpy :: Ptr a -> Ptr b -> Int -> IO () Source

Copy memory into a destination (in the first argument) from a source (in the second argument).

safeFreeFunPtr :: Ptr a -> IO () Source

Same as freeHaskellFunPtr, but it does nothing when given a nullPtr.

maybeReleaseFunPtr :: Maybe (Ptr (FunPtr a)) -> IO () Source

If given a pointer to the memory location, free the FunPtr at that location, and then the pointer itself. Useful for freeing the memory associated to callbacks which are called just once, with no destroy notification.

checkUnexpectedReturnNULL :: Text -> Ptr a -> IO () Source

Check that the given pointer is not NULL. If it is, raise a UnexpectedNullPointerReturn exception.

checkUnexpectedNothing :: Text -> IO (Maybe a) -> IO a Source

An annotated version of fromJust, which raises a UnexpectedNullPointerReturn in case it encounters a Nothing.