nonblocking 模式 如果send时缓冲区满，返回-1（表示错误），还是0（表示发了0字节）

mubing_s

nonblocking 模式 如果send时缓冲区满，返回-1（表示错误），还是0（表示发了0字节）？？？求大神解答

linux_c_py_php

-1 , errno == EAGAIN.

kevin_zcwen

-1, errno == EAGAIN || errno == EWOULDBLOCK

sunlan

    The send() function shall fail if:

    [EAGAIN] or [EWOULDBLOCK]

        The socket's file descriptor is marked O_NONBLOCK and the requested operation would block.
    [EBADF]
        The socket argument is not a valid file descriptor.
    [ECONNRESET]
        A connection was forcibly closed by a peer.
    [EDESTADDRREQ]

        The socket is not connection-mode and no peer address is set.
    [EINTR]
        A signal interrupted send() before any data was transmitted.
    [EMSGSIZE]
        The message is too large to be sent all at once, as the socket requires.
    [ENOTCONN]
        The socket is not connected.
    [ENOTSOCK]
        The socket argument does not refer to a socket.
    [EOPNOTSUPP]
        The socket argument is associated with a socket that does not support one or more of the values set in flags.
    [EPIPE]
        The socket is shut down for writing, or the socket is connection-mode and is no longer connected. In the latter case, and if the socket is of type SOCK_STREAM or SOCK_SEQPACKET and the MSG_NOSIGNAL flag is not set, the SIGPIPE signal is generated to the calling thread.

    The send() function may fail if:

    [EACCES]
        The calling process does not have appropriate privileges.
    [EIO]
        An I/O error occurred while reading from or writing to the file system.
    [ENETDOWN]
        The local network interface used to reach the destination is down.
    [ENETUNREACH]

        No route to the network is present.
    [ENOBUFS]
        Insufficient resources were available in the system to perform the operation.