System.Socket.Internal.Socket

Documentation

newtype Socket d t p

A generic socket type. Also see socket for details.

The socket is just an MVar-wrapped file descriptor. It is exposed in order to make this library easily extensible, but it is usually not necessary nor advised to work directly on the file descriptor. If you do, the following rules must be obeyed:

• Make sure not to deadlock. Use withMVar or similar.
• The lock must not be held during a blocking call. This would make it impossible to send and receive simultaneously or to close the socket.
• The lock must be held when calling operations that use the file descriptor. Otherwise the socket might get closed or even reused by another thread/capability which might result in reading from or writing totally different connection. This is a security nightmare!
• The socket is non-blocking and all the code relies on that assumption. You need to use GHC's eventing mechanism primitives to block until something happens. The former rules forbid to use threadWaitRead as it does not seperate between registering the file descriptor (for which the lock must be held) and the actual waiting (for which you must not hold the lock). Also see this thread and read the library code to see how the problem is currently circumvented.

Constructors

Socket (MVar Fd)

newtype SocketException

Constructors

SocketException Errno

Instances

Show SocketException

Exception SocketException

newtype MsgFlags

Constructors

MsgFlags CInt

Instances

Monoid MsgFlags

msgEOR :: MsgFlags

msgOOB :: MsgFlags

msgNOSIGNAL :: MsgFlags

class GetSockOpt o where

Methods

getSockOpt :: Socket f t p -> IO o

Instances

GetSockOpt SO_ACCEPTCONN

class SetSockOpt o where

Methods

setSockOpt :: Socket f t p -> o -> IO ()

data SO_ACCEPTCONN

Constructors

SO_ACCEPTCONN Bool

Instances

GetSockOpt SO_ACCEPTCONN