text: accept - accept a new connection on a socket
  #include <sys/socket.h> int accept (int socket, struct sockaddr *address, socklen_t *address_len);
  The accept() function extracts the first connection on the queue of pending connections, creates a new socket with the same socket type protocol and address family as the specified socket, and allocates a new file descriptor for that socket.
  The will be returned.
  - address_len
  - Points to a socklen_t which on input specifies the length of the supplied sockaddr structure, and on output specifies the length of the stored address.
  If address is not a null pointer, the address of the peer for the accepted connection is stored in the sockaddr structure pointed to by address, and the length of this address is stored in the object pointed to by address_len.() will block until a connection is present. If the listen() queue is empty of connection requests and O_NONBLOCK is set on the file descriptor for the socket, accept() will fail and set errno to [EAGAIN] or [EWOULDBLOCK].
  The accepted socket cannot itself accept more connections. The original socket remains open and can accept more connections.
  Upon successful completion, accept() returns the nonnegative file descriptor of the accepted socket. Otherwise, -1 is returned and errno is set to indicate the error.
  The accept() function will fail if:
  - [EAGAIN] or [EWOULDBLOCK]
  O_NONBLOCK is set for the socket file descriptor and no connections are present to be accepted.
  - [EBADF]
  - The socket argument is not a valid file descriptor.
  - [ECONNABORTED]
  - A connection has been aborted.
  - [EFAULT]
  - The address or address_len parameter can not be accessed or written.
  - .
  - [ENOSR]
  - There was insufficient STREAMS resources available to complete the operation.
  - [EPROTO]
  - A protocol error has occurred; for example, the STREAMS protocol stack has not been initialised.
  When a connection is available, select() will indicate that the file descriptor for the socket is ready for reading.
  bind(), connect(), listen(), socket(), <sys/socket.h>.