EAGAIN The file descriptor fd refers to the file other than a socket and has long been marked nonblocking (O_NONBLOCK), as well as write would block. See open(2) for further information about the O_NONBLOCK flag. EAGAIN or EWOULDBLOCK The file descriptor fd refers to the socket and continues to be https://www.youtube.com/channel/UCTleG6-484F7WHZD0hAjRRw