Sends a message on a socket. Attempts to send the scalar MSG to the SOCKET filehandle. Takes the same flags as the system call of the same name. On unconnected sockets you must specify a destination to send TO, in which case it does a C
sendto. Returns the number of characters sent, or the undefined value if there is an error. The C system call sendmsg(2) is currently unimplemented. See "UDP: Message Passing" in perlipc for examples.
Note the characters: depending on the status of the socket, either (8-bit) bytes or characters are sent. By default all sockets operate on bytes, but for example if the socket has been changed using binmode() to operate with the
:utf8 I/O layer (see "open", or the
open pragma, open), the I/O will operate on characters, not bytes.