On Tue, Dec 8, 2009 at 3:22 AM, Magicloud Magiclouds wrote:

Hi,  I am warping some C libs. In one function, I do this: 183  allocaBytes bufLen $ \buf -> do 184    ret <- {# call buf_read #} 185      bluh 186      bala 187      buf 188      bufLen 189    if ret < 0 190      then userError "bufRead error" 191      else -- what should I do here?

 I am thinking about bytestring, to pass the content of the buf to the outside of the function. But I am not sure.  What should I do?

See: Data.ByteString.Internal.createAndTrim: http://hackage.haskell.org/packages/archive/bytestring/0.9.1.4/doc/html/Data... With that your program becomes something like: createAndTrim bufLen $ \buf -> ret <- {# call buf_read #} bluh bala buf bufLen if ret < 0 then userError "bufRead error" else return ret -- if ret indicates the number of bytes read regards, Bas