Data.Capnp.IO

This module provides utilities for reading and writing values to and from file Handles.

Documentation

hGetValue :: FromStruct ConstMsg a => Handle -> Int -> IO a

hGetValue limit handle reads a message from handle, returning its root object. limit is used as both a cap on the size of a message which may be read and, for types in the high-level API, the traversal limit when decoding the message.

It may throw a Error if there is a problem decoding the message, or an IOError raised by the underlying IO libraries.

getValue :: FromStruct ConstMsg a => Int -> IO a

getValue is equivalent to hGetValue stdin.

hPutValue :: (Cerialize RealWorld a, ToStruct (MutMsg RealWorld) (Cerial (MutMsg RealWorld) a)) => Handle -> a -> IO ()

hPutValue handle value writes value to handle, as the root object of a message. If it throws an exception, it will be an IOError raised by the underlying IO libraries.

putValue :: (Cerialize RealWorld a, ToStruct (MutMsg RealWorld) (Cerial (MutMsg RealWorld) a)) => a -> IO ()

putValue is equivalent to hPutValue stdin

hGetMsg :: Handle -> Int -> IO ConstMsg

hGetMsg handle limit reads a message from handle that is at most limit 64-bit words in length.

getMsg :: Int -> IO ConstMsg

Equivalent to hGetMsg stdin

hPutMsg :: Handle -> ConstMsg -> IO ()

hPutMsg handle msg writes msg to handle. If there is an exception, it will be an IOError raised by the underlying IO libraries.

putMsg :: ConstMsg -> IO ()

Equivalent to hPutMsg stdout