The abstract type representing the read or write end of a BroadcastChan.

Used with DataKinds as phantom type indicating whether a BroadcastChan value is a read or write end.

Alias for the In type from the Direction kind, allows users to write the BroadcastChan In a type without enabling DataKinds.

Alias for the Out type from the Direction kind, allows users to write the BroadcastChan Out a type without enabling DataKinds.

Creates a new BroadcastChan write end.

Create a new read end for a BroadcastChan.

BroadcastChan In:

Will receive all messages written to the channel after this read end is created.

BroadcastChan Out:

Will receive all currently unread messages and all future messages.

Read the next value from the read end of a BroadcastChan. Returns Nothing if the BroadcastChan is closed and empty. See BroadcastChan.Throw.readBChan for an exception throwing variant.

Write a value to write end of a BroadcastChan. Any messages written while there are no live read ends are dropped on the floor and can be immediately garbage collected, thus avoiding space leaks.

The return value indicates whether the write succeeded, i.e., True if the message was written, False is the channel is closed. See BroadcastChan.Throw.writeBChan for an exception throwing variant.

Close a BroadcastChan, disallowing further writes. Returns True if the BroadcastChan was closed. Returns False if the BroadcastChan was already closed.

Check whether a BroadcastChan is closed. True meaning that future read/write operations on the channel will always fail.

BroadcastChan In:

True indicates the channel is closed and writes will always fail.

Beware of TOC-TOU races: It is possible for a BroadcastChan to be closed by another thread. If multiple threads use the same channel a closeBChan from another thread can result in the channel being closed right after isClosedBChan returns.

BroadcastChan Out:

True indicates the channel is both closed and empty, meaning reads will always fail.

Return a lazy list representing the messages written to the channel.

Uses unsafeInterleaveIO to defer the IO operations.

BroadcastChan In:

The list contains every message written to the channel after this IO action completes.

BroadcastChan Out:

The list contains every currently unread message and all future messages. It's safe to keep using the original channel in any thread.

Unlike getChanContents from Control.Concurrent, the list resulting from this function is not affected by reads on the input channel. Every message that is unread or written after the IO action completes will end up in the result list.

Action to take when an exception occurs while processing an element.

Exception handler for parallel processing.

Map a monadic function over a Foldable, processing elements in parallel.

This function does NOT guarantee that elements are processed in a deterministic order!

Like parMapM_, but folds the individual results into single result value.

This function does NOT guarantee that elements are processed in a deterministic order!

Like parFoldMap, but uses a monadic fold function.

This function does NOT guarantee that elements are processed in a deterministic order!

Strict fold of the BroadcastChan​'s messages. Can be used with Control.Foldl from Tekmo's foldl package:

Control.Foldl.purely foldBChan :: (MonadIO m, MonadIO n) => Fold a b -> BroadcastChan d a -> n (m b)

The result of this function is a nested monadic value to give more fine-grained control/separation between the start of listening for messages and the start of processing. The inner action folds the actual messages and completes when the channel is closed and exhausted. The outer action controls from when on messages are received. Specifically:

BroadcastChan In:

Will process all messages sent after the outer action completes.

BroadcastChan Out:

Will process all messages that are unread when the outer action completes, as well as all future messages.

After the outer action completes the fold is unaffected by other (concurrent) reads performed on the original channel. So it's safe to reuse the channel.

Strict, monadic fold of the BroadcastChan​'s messages. Can be used with Control.Foldl from Tekmo's foldl package:

Control.Foldl.impurely foldBChanM :: (MonadIO m, MonadIO n) => FoldM m a b -> BroadcastChan d a -> n (m b)

Has the same behaviour and guarantees as foldBChan.