#### 16.9.5 Transferring Data

Once a socket has been connected to a peer, you can use the ordinary `read` and `write` operations (see I/O Primitives) to transfer data. A socket is a two-way communications channel, so read and write operations can be performed at either end.

There are also some I/O modes that are specific to socket operations. In order to specify these modes, you must use the `recv` and `send` functions instead of the more generic `read` and `write` functions. The `recv` and `send` functions take an additional argument which you can use to specify various flags to control special I/O modes. For example, you can specify the `MSG_OOB` flag to read or write out-of-band data, the `MSG_PEEK` flag to peek at input, or the `MSG_DONTROUTE` flag to control inclusion of routing information on output.