QT Qabstractsocket SocketError and some network programming uses the value of __ programming

Recently in a QT program to modify the code, basically the problem is to find out what the problem is the following is about the Qabstractsocket::socketerror value

And some other values, it's still useful.

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

Lists the network-level protocols used by QT, such as IP4,IP6. 2.enum Qiodevice::openmodeflag
Flags Qiodevice::openmode

This are used with open () to describe the "mode" 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 into append mode, so this 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.

Lists the status of the open device. If the device is not open, open it as read-only and open it in writing.

3.enum Qabstractsocket::socketerror

This enum describes the socket errors that can occur.

Constant	Value	Description
Qabstractsocket::connectionrefusederror	0	The connection is refused by the peer (or timed out).
Qabstractsocket::remotehostclosederror	1	The remote host closed the connection. The client socket (i.e., this socket) is closed after the remote close notification has been sent.
Qabstractsocket::hostnotfounderror	2	The host address is 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 (e.g., too many sockets).
Qabstractsocket::sockettimeouterror	5	The socket operation timed out.
Qabstractsocket::D atagramtoolargeerror	6	The datagram was larger than the operating system ' s limit (which can is as low as 8192 bytes).
Qabstractsocket::networkerror	7	An error occurred with the network (e.g., the network cable is accidentally out).
Qabstractsocket::addressinuseerror	8	The address, specified to Qudpsocket::bind (), already in-use and being set to being exclusive.
Qabstractsocket::socketaddressnotavailableerror	9	The address specified to Qudpsocket::bind () does is not belong to the host.
Qabstractsocket::unsupportedsocketoperationerror	10	The requested socket operation isn't supported by the local operating system (e.g., lack of IPv6).
Qabstractsocket::P roxyauthenticationrequirederror	12	The socket is using a proxy, and the proxy requires authentication.
Qabstractsocket::sslhandshakefailederror	13	The Ssl/tls handshake failed, so the connection is 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::P roxyconnectionrefusederror	14	Could not contacts the proxy server because the connection to that server is denied
Qabstractsocket::P roxyconnectionclosederror	15	The connection to the proxy server is closed unexpectedly (before the connection to the final peer is established)
Qabstractsocket::P roxyconnectiontimeouterror	16	The connection to the proxy server, timed out, or the proxy server stopped responding in the authentication phase.
Qabstractsocket::P roxynotfounderror	17	The proxy address set with SetProxy () (or the application proxy) is not found.
Qabstractsocket::P roxyprotocolerror	18	The connection negotiation with the proxy server because the response from the proxy server could is not understood.
Qabstractsocket::unknownsocketerror	-1	An unidentified error occurred.

Lists errors that may occur in the connection, and error one by one is listed in the previous table.

4.enum qabstractsocket::socketstate

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

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 a and port (for servers).
Qabstractsocket::closingstate	6	The ' socket is ' about to close ' (data may still being waiting to be written).
Qabstractsocket::listeningstate	5	For internal.

Lists the connection status of a socket

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

also Qabstractsocket::sockettype ().

Lists the ways in which sockets are connected.

The contents of the

table will be sorted later, thank you.