Memory-managed wrapper type.

A convenience alias for Nothing :: Maybe PollableInputStream.

Type class for types which can be safely cast to PollableInputStream, for instance with toPollableInputStream.

Cast to PollableInputStream, for types for which this is known to be safe. For general casts, use castTo.

Checks if stream is actually pollable. Some classes may implement PollableInputStream but have only certain instances of that class be pollable. If this method returns False, then the behavior of other PollableInputStream methods is undefined.

For any given stream, the value returned by this method is constant; a stream cannot switch from pollable to non-pollable or vice versa.

Since: 2.28

Creates a Source that triggers when stream can be read, or cancellable is triggered or an error occurs. The callback on the source is of the PollableSourceFunc type.

As with pollableInputStreamIsReadable, it is possible that the stream may not actually be readable even after the source triggers, so you should use pollableInputStreamReadNonblocking rather than inputStreamRead from the callback.

Since: 2.28

Checks if stream can be read.

Note that some stream types may not be able to implement this 100% reliably, and it is possible that a call to inputStreamRead after this returns True would still block. To guarantee non-blocking behavior, you should always use pollableInputStreamReadNonblocking, which will return a IOErrorEnumWouldBlock error rather than blocking.

Since: 2.28

Attempts to read up to count bytes from stream into buffer, as with inputStreamRead. If stream is not currently readable, this will immediately return IOErrorEnumWouldBlock, and you can use pollableInputStreamCreateSource to create a Source that will be triggered when stream is readable.

Note that since this method never blocks, you cannot actually use cancellable to cancel it. However, it will return an error if cancellable has already been cancelled when you call, which may happen if you call this method after a source triggers due to having been cancelled.