Capnp.IO

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

Documentation

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

getValue is equivalent to hGetValue stdin.

sGetMsg :: Socket -> WordCount -> IO ConstMsg

Like hGetMsg, except that it takes a socket instead of a Handle.

sGetValue :: FromStruct ConstMsg a => Socket -> WordCount -> IO a

Like hGetValue, except that it takes a socket instead of a Handle.

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

putValue is equivalent to hPutValue stdin

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

Like hPutValue, except that it takes a Socket instead of a Handle.

sPutMsg :: Socket -> ConstMsg -> IO ()

Like hPutMsg, except that it takes a Socket instead of a Handle.

hGetMsg :: Handle -> WordCount -> IO ConstMsg

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

getMsg :: WordCount -> 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