what errors does net.Conn.Write return

Question

According to the go documentation, the net.Conn.Write() function will return an error, if it could not send all bytes in the given slice.

How do I know which type of error is returned in this case? Should I just check if there is an error, and if n > 0 and n < len(p) ? Or is it enough to just check if n < len(p) alone? Are there unrecoverable errors for which n < len(p) ?

Say I want to send X gigabytes of data for example. What would a "correct" Write() loop look like?

If the output buffers are full, will Write() simply just block until it has sent everything from p? making a check for n < len(p) superfluous?

Answer 1

Well, net.Conn is an interface. This means that it is completely up to the implementation to determine which errors to send back. A TCP connection and UNIX socket connection can have very different reasons why a write can't be fully completed.

The net.Conn.Write signature is exactly the same as the io.Writer signature. Which means that every implementation of net.Conn also implements io.Writer. So you can use any existing method like io.Copy or io.CopyN to write data to a connection.