Re: [Haskell-cafe] hSetBuffering woes

Bryan O'Sullivan wrote:

Eric wrote:

...

I tried to turn off buffering with the command hSetBuffering (from System.IO) but my app still blocks on hGetContents (from Data.ByteString). Does anyone know what's happening?

The hGetContents function can't behave the way you want, because it's defined to return the entire rest of the input stream.

If you want to stick with strict ByteStrings, use hGetNonBlocking instead, but you'll need to block between reads of the handle yourself, using System.IO.hWaitForInput.

Otherwise, use lazy ByteStrings. That version of hGetContents will lazily yield chunks that are as big as can be read without blocking as they arrive (up to a limit of 64KB), and will hWaitForInput for you.

I've converted to lazy bytestrings. After reading in the bytes from a network connection I want to save them to a file but now the appendFile function blocks: import Data.ByteString.Lazy as LazyBits(ByteString, empty, hGetContents, writeFile, appendFile) ... LazyBits.appendFile filepath bits -- this blocks now! How can I fix this? E.