QTcpSocket类中文参考（一）

     近日要用Qt设计路灯节能监控系统的上位机，用到QTcpSocket类，参考文档英文的，看起来不方便，按学习笔记的方式，归纳如下：

  1. enum QAbstractSocket::NetworkLayerProtocol

This enum describes the network layer protocol values used in Qt.

Constant	Value	Description
QAbstractSocket::IPv4Protocol	0	IPv4
QAbstractSocket::IPv6Protocol	1	IPv6
QAbstractSocket::UnknownNetworkLayerProtocol	-1	Other than IPv4 and IPv6

  列出了Qt使用的网络层次协议，如IP4，IP6.

2.enum QIODevice::OpenModeFlag
flags QIODevice::OpenMode

This enum is used with open() to describe the mode in which a device is opened. It is also returned by openMode().

Constant	Value	Description
QIODevice::NotOpen	0x0000	The device is not open.
QIODevice::ReadOnly	0x0001	The device is open for reading.
QIODevice::WriteOnly	0x0002	The device is open for writing.
QIODevice::ReadWrite	ReadOnly | WriteOnly	The device is open for reading and writing.
QIODevice::Append	0x0004	The device is opened in append mode, so that all data is written to the end of the file.
QIODevice::Truncate	0x0008	If possible, the device is truncated before it is opened. All earlier contents of the device are lost.
QIODevice::Text	0x0010	When reading, the end-of-line terminators are translated to '\n'. When writing, the end-of-line terminators are translated to the local encoding, for example '\r\n' for Win32.
QIODevice::Unbuffered	0x0020	Any buffer in the device is bypassed.

列出了打开设备的状态。如设备未打开，以只读的方式打开，以写的方式打开。

3.enum QAbstractSocket::SocketError

This enum describes the socket errors that can occur.

Constant	Value	Description
QAbstractSocket::ConnectionRefusedError	0	The connection was refused by the peer (or timed out).
QAbstractSocket::RemoteHostClosedError	1	The remote host closed the connection. Note that the client socket (i.e., this socket) will be closed after the remote close notification has been sent.
QAbstractSocket::HostNotFoundError	2	The host address was not found.
QAbstractSocket::SocketAccessError	3	The socket operation failed because the application lacked the required privileges.
QAbstractSocket::SocketResourceError	4	The local system ran out of resources (e.g., too many sockets).
QAbstractSocket::SocketTimeoutError	5	The socket operation timed out.
QAbstractSocket::DatagramTooLargeError	6	The datagram was larger than the operating system's limit (which can be as low as 8192 bytes).
QAbstractSocket::NetworkError	7	An error occurred with the network (e.g., the network cable was accidentally plugged out).
QAbstractSocket::AddressInUseError	8	The address specified to QUdpSocket::bind() is already in use and was set to be exclusive.
QAbstractSocket::SocketAddressNotAvailableError	9	The address specified to QUdpSocket::bind() does not belong to the host.
QAbstractSocket::UnsupportedSocketOperationError	10	The requested socket operation is not supported by the local operating system (e.g., lack of IPv6 support).
QAbstractSocket::ProxyAuthenticationRequiredError	12	The socket is using a proxy, and the proxy requires authentication.
QAbstractSocket::SslHandshakeFailedError	13	The SSL/TLS handshake failed, so the connection was closed (only used in QSslSocket)
QAbstractSocket::UnfinishedSocketOperationError	11	Used by QAbstractSocketEngine only, The last operation attempted has not finished yet (still in progress in the background).
QAbstractSocket::ProxyConnectionRefusedError	14	Could not contact the proxy server because the connection to that server was denied
QAbstractSocket::ProxyConnectionClosedError	15	The connection to the proxy server was closed unexpectedly (before the connection to the final peer was established)
QAbstractSocket::ProxyConnectionTimeoutError	16	The connection to the proxy server timed out or the proxy server stopped responding in the authentication phase.
QAbstractSocket::ProxyNotFoundError	17	The proxy address set with setProxy() (or the application proxy) was not found.
QAbstractSocket::ProxyProtocolError	18	The connection negotiation with the proxy server because the response from the proxy server could not be understood.
QAbstractSocket::UnknownSocketError	-1	An unidentified error occurred.

列出了连接中可能发 生的错误，错误一一列在上表中。

4.enum QAbstractSocket::SocketState

This enum describes the different states in which a socket can be.

Constant	Value	Description
QAbstractSocket::UnconnectedState	0	The socket is not connected.
QAbstractSocket::HostLookupState	1	The socket is performing a host name lookup.
QAbstractSocket::ConnectingState	2	The socket has started establishing a connection.
QAbstractSocket::ConnectedState	3	A connection is established.
QAbstractSocket::BoundState	4	The socket is bound to an address and port (for servers).
QAbstractSocket::ClosingState	6	The socket is about to close (data may still be waiting to be written).
QAbstractSocket::ListeningState	5	For internal use only.

列出了套接字的连接状态

5.enum QAbstractSocket::SocketType

This enum describes the transport layer protocol.

Constant	Value	Description
QAbstractSocket::TcpSocket	0	TCP
QAbstractSocket::UdpSocket	1	UDP
QAbstractSocket::UnknownSocketType	-1	Other than TCP and UDP

See also QAbstractSocket::socketType().

列出了套接字的连接方式。

表里面的内容以后有空整理，谢谢！