IPWorks 2022 C++ Edition
Version 22.0 [Build 8369]

UDP Class

Properties   Methods   Events   Config Settings   Errors  

The UDP class is used to facilitate UDP (datagram) communications. It can act both as a client and a server and communicate with any number of hosts simultaneously, as well as generate and receive broadcast packets.

Syntax

UDP

Remarks

The interface of the class is similar to the interface of TCPClient, only much simpler. The class is activated/deactivated through the Active property. This property enables or disables sends or receives. The data can be sent in the same way as TCPClient, using the Send method and specifying the text to send. This is identical to assigning data to the DataToSend property. The destination is specified using the RemoteHost and RemotePort properties. Inbound data is received through the DataIn event.

If the UseConnection config setting is set to True, then a local association is created with the remote host. Otherwise, the class can receive datagrams (packets) from any host, and send datagrams to any host. Packets can be broadcast on the local net by setting the destination (RemoteHost) to 255.255.255.255.

The operation of the class is almost completely asynchronous. All calls, except the ones that deal with domain name resolution, operate through Windows messages (no blocking calls). The gain in performance is considerable when compared to using blocking calls.

Property List

The following is the full list of the properties of the class with short descriptions. Click on the links for further details.

AcceptDataThis property enables or disables data reception (the DataIn event).
ActiveIndicates whether the class is active.
DontRouteIf this property is set to True, it forces the socket to send data directly to the interface (no routing).
LocalHostThe name of the local host or user-assigned IP interface through which connections are initiated or accepted.
LocalPortThe UDP port in the local host where UDP binds.
RemoteHostThe address of the remote host. Domain names are resolved to IP addresses.
RemotePortThe UDP port in the remote host.
TimeToLiveThe maximum number of subnets that a datagram can traverse.

Method List

The following is the full list of the methods of the class with short descriptions. Click on the links for further details.

ActivateEnables sending and receiving of data.
ConfigSets or retrieves a configuration setting.
DeactivateDisables sending and receive of data.
DoEventsProcesses events from the internal message queue.
PauseDataThis method pauses data reception.
ProcessDataThis method reenables data reception after a call to PauseData .
ResetReset the class.
ResolveRemoteHostResolves the hostname in RemoteHost to an IP address.
SendSend data to the remote host.
SendBytesSend data to the remote host.
SendTextSend data to the remote host.

Event List

The following is the full list of the events fired by the class with short descriptions. Click on the links for further details.

DataInFired when data is received.
ErrorInformation about errors during data delivery.
ReadyToSendFired when the class is ready to send data.

Config Settings

The following is a list of config settings for the class with short descriptions. Click on the links for further details.

CaptureIPPacketInfoUsed to capture the packet information.
DelayHostResolutionWhether the hostname is resolved when RemoteHost is set.
DestinationAddressUsed to get the destination address from the packet information.
DontFragmentUsed to set the Don't Fragment flag of outgoing packets.
LocalHostThe name of the local host through which connections are initiated or accepted.
LocalPortThe port in the local host where the class binds.
MaxPacketSizeThe maximum length of the packets that can be received.
QOSDSCPValueUsed to specify an arbitrary QOS/DSCP setting (optional).
QOSTrafficTypeUsed to specify QOS/DSCP settings (optional).
ShareLocalPortIf set to True, allows more than one instance of the class to be active on the same local port.
SourceIPAddressUsed to set the source IP address used when sending a packet.
SourceMacAddressUsed to set the source MAC address used when sending a packet.
UseConnectionDetermines whether to use a connected socket.
UseIPv6Whether or not to use IPv6.
AbsoluteTimeoutDetermines whether timeouts are inactivity timeouts or absolute timeouts.
FirewallDataUsed to send extra data to the firewall.
InBufferSizeThe size in bytes of the incoming queue of the socket.
OutBufferSizeThe size in bytes of the outgoing queue of the socket.
BuildInfoInformation about the product's build.
CodePageThe system code page used for Unicode to Multibyte translations.
LicenseInfoInformation about the current license.
ProcessIdleEventsWhether the class uses its internal event loop to process events when the main thread is idle.
SelectWaitMillisThe length of time in milliseconds the class will wait when DoEvents is called if there are no events to process.
UseInternalSecurityAPITells the class whether or not to use the system security libraries or an internal implementation.

AcceptData Property (UDP Class)

This property enables or disables data reception (the DataIn event).

Syntax

ANSI (Cross Platform)
int GetAcceptData();
int SetAcceptData(int bAcceptData);

Unicode (Windows)
BOOL GetAcceptData();
INT SetAcceptData(BOOL bAcceptData);

int ipworks_udp_getacceptdata(void* lpObj);
int ipworks_udp_setacceptdata(void* lpObj, int bAcceptData);

bool GetAcceptData();
int SetAcceptData(bool bAcceptData);

Default Value

TRUE

Remarks

This property enables or disables data reception (the DataIn event). Setting this property to False, temporarily disables data reception (and the DataIn event). Setting this property to True, reenables data reception.

Note: It is recommended to use the PauseData or ProcessData method instead of setting this property.

This property is not available at design time.

Data Type

Boolean

Active Property (UDP Class)

Indicates whether the class is active.

Syntax

ANSI (Cross Platform)
int GetActive();
int SetActive(int bActive);

Unicode (Windows)
BOOL GetActive();
INT SetActive(BOOL bActive);

int ipworks_udp_getactive(void* lpObj);
int ipworks_udp_setactive(void* lpObj, int bActive);

bool GetActive();
int SetActive(bool bActive);

Default Value

FALSE

Remarks

This property indicates whether the class is currently active and can send or receive data.

If UseConnection is set to True, then a local association (connection) to the remote host and port is also created.

Note: Use the Activate or Deactivate method to control whether the class is active.

This property is not available at design time.

Data Type

Boolean

DontRoute Property (UDP Class)

If this property is set to True, it forces the socket to send data directly to the interface (no routing).

Syntax

ANSI (Cross Platform)
int GetDontRoute();
int SetDontRoute(int bDontRoute);

Unicode (Windows)
BOOL GetDontRoute();
INT SetDontRoute(BOOL bDontRoute);

int ipworks_udp_getdontroute(void* lpObj);
int ipworks_udp_setdontroute(void* lpObj, int bDontRoute);

bool GetDontRoute();
int SetDontRoute(bool bDontRoute);

Default Value

FALSE

Remarks

If this property is set to True, it forces the socket to send data directly to the interface (no routing). Normally, IP sockets send packets of data through routers and gateways until they reach the final destination. If this property is set to True, then data will be delivered on the local subnet only.

This property is not available at design time.

Data Type

Boolean

LocalHost Property (UDP Class)

The name of the local host or user-assigned IP interface through which connections are initiated or accepted.

Syntax

ANSI (Cross Platform)
char* GetLocalHost();
int SetLocalHost(const char* lpszLocalHost);

Unicode (Windows)
LPWSTR GetLocalHost();
INT SetLocalHost(LPCWSTR lpszLocalHost);

char* ipworks_udp_getlocalhost(void* lpObj);
int ipworks_udp_setlocalhost(void* lpObj, const char* lpszLocalHost);

QString GetLocalHost();
int SetLocalHost(QString qsLocalHost);

Default Value

""

Remarks

The LocalHost property contains the name of the local host as obtained by the gethostname() system call, or if the user has assigned an IP address, the value of that address.

In multi-homed hosts (machines with more than one IP interface) setting LocalHost to the value of an interface will make the class initiate connections (or accept in the case of server classs) only through that interface.

If the class is connected, the LocalHost property shows the IP address of the interface through which the connection is made in internet dotted format (aaa.bbb.ccc.ddd). In most cases, this is the address of the local host, except for multi-homed hosts (machines with more than one IP interface).

NOTE: LocalHost is not persistent. You must always set it in code, and never in the property window.

Data Type

String

LocalPort Property (UDP Class)

The UDP port in the local host where UDP binds.

Syntax

ANSI (Cross Platform)
int GetLocalPort();
int SetLocalPort(int iLocalPort);

Unicode (Windows)
INT GetLocalPort();
INT SetLocalPort(INT iLocalPort);

int ipworks_udp_getlocalport(void* lpObj);
int ipworks_udp_setlocalport(void* lpObj, int iLocalPort);

int GetLocalPort();
int SetLocalPort(int iLocalPort);

Default Value

0

Remarks

The LocalPort property must be set before UDP is activated (Active is set to True). It instructs the class to bind to a specific port (or communication endpoint) in the local machine.

Setting it to 0 (default) enables the TCP/IP stack to choose a port at random. The chosen port will be shown by the LocalPort property after the connection is established.

LocalPort cannot be changed once the class is Active. Any attempt to set the LocalPort property when the class is Active will generate an error.

The LocalPort property is useful when trying to connect to services that require a trusted port in the client side.

Data Type

Integer

RemoteHost Property (UDP Class)

The address of the remote host. Domain names are resolved to IP addresses.

Syntax

ANSI (Cross Platform)
char* GetRemoteHost();
int SetRemoteHost(const char* lpszRemoteHost);

Unicode (Windows)
LPWSTR GetRemoteHost();
INT SetRemoteHost(LPCWSTR lpszRemoteHost);

char* ipworks_udp_getremotehost(void* lpObj);
int ipworks_udp_setremotehost(void* lpObj, const char* lpszRemoteHost);

QString GetRemoteHost();
int SetRemoteHost(QString qsRemoteHost);

Default Value

""

Remarks

The RemoteHost property specifies the IP address (IP number in dotted internet format) or Domain Name of the remote host.

If RemoteHost is set to 255.255.255.255, the class broadcasts data on the local subnet.

If the RemoteHost property is set to a Domain Name, a DNS request is initiated and upon successful termination of the request, the RemoteHost property is set to the corresponding address. If the search is not successful, an error is returned.

If UseConnection is set to True, the RemoteHost must be set before the class is activated (Active is set to True).

Data Type

String

RemotePort Property (UDP Class)

The UDP port in the remote host.

Syntax

ANSI (Cross Platform)
int GetRemotePort();
int SetRemotePort(int iRemotePort);

Unicode (Windows)
INT GetRemotePort();
INT SetRemotePort(INT iRemotePort);

int ipworks_udp_getremoteport(void* lpObj);
int ipworks_udp_setremoteport(void* lpObj, int iRemotePort);

int GetRemotePort();
int SetRemotePort(int iRemotePort);

Default Value

0

Remarks

The RemotePort is the UDP port on the RemoteHost to send UDP datagrams to.

A valid port number (a value between 1 and 65535) is required.

If UseConnection is set to True, the RemotePort must be set before the class is activated (Active is set to True).

Data Type

Integer

TimeToLive Property (UDP Class)

The maximum number of subnets that a datagram can traverse.

Syntax

ANSI (Cross Platform)
int GetTimeToLive();
int SetTimeToLive(int iTimeToLive);

Unicode (Windows)
INT GetTimeToLive();
INT SetTimeToLive(INT iTimeToLive);

int ipworks_udp_gettimetolive(void* lpObj);
int ipworks_udp_settimetolive(void* lpObj, int iTimeToLive);

int GetTimeToLive();
int SetTimeToLive(int iTimeToLive);

Default Value

0

Remarks

The default value for this property is 0, which tells the class to use the default TTL value of the underlying TCP/IP subsystem. Depending on the application, you can specify a value between 1 and 255.

Data Type

Integer

Activate Method (UDP Class)

Enables sending and receiving of data.

Syntax

ANSI (Cross Platform)
int Activate();

Unicode (Windows)
INT Activate();

int ipworks_udp_activate(void* lpObj);

int Activate();

Remarks

This method enables sending and receiving of data. When called the class will create a communication endpoint (socket) which can be used for sending and receiving UDP messages. This method must be called before using the class to send and receive data.

If the UseConnection configuration setting is set to true, then a local association (connection) to the remote host is also created.

Error Handling (C++)

This method returns a result code; 0 indicates success, while a non-zero error code indicates that this method encountered an error during its execution. If an error occurs, the GetLastError() method can be called to retrieve the associated error message. (Note: This method's result code can also be obtained by calling the GetLastErrorCode() method after it returns.)

Config Method (UDP Class)

Sets or retrieves a configuration setting.

Syntax

ANSI (Cross Platform)
char* Config(const char* lpszConfigurationString);

Unicode (Windows)
LPWSTR Config(LPCWSTR lpszConfigurationString);

char* ipworks_udp_config(void* lpObj, const char* lpszConfigurationString);

QString Config(const QString& qsConfigurationString);

Remarks

Config is a generic method available in every class. It is used to set and retrieve configuration settings for the class.

These settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the class, access to these internal properties is provided through the Config method.

To set a configuration setting named PROPERTY, you must call Config("PROPERTY=VALUE"), where VALUE is the value of the setting expressed as a string. For boolean values, use the strings "True", "False", "0", "1", "Yes", or "No" (case does not matter).

To read (query) the value of a configuration setting, you must call Config("PROPERTY"). The value will be returned as a string.

Error Handling (C++)

This method returns a String value; after it returns, call the GetLastErrorCode() method to obtain its result code; 0 indicates success, while a non-zero error code indicates that this method encountered an error during its execution. If an error occurs, the GetLastError() method can be called to retrieve the associated error message.

Deactivate Method (UDP Class)

Disables sending and receive of data.

Syntax

ANSI (Cross Platform)
int Deactivate();

Unicode (Windows)
INT Deactivate();

int ipworks_udp_deactivate(void* lpObj);

int Deactivate();

Remarks

This method disables sending and receiving of data. When called the class will destroy the existing socket and disable data communications.

Error Handling (C++)

This method returns a result code; 0 indicates success, while a non-zero error code indicates that this method encountered an error during its execution. If an error occurs, the GetLastError() method can be called to retrieve the associated error message. (Note: This method's result code can also be obtained by calling the GetLastErrorCode() method after it returns.)

DoEvents Method (UDP Class)

Processes events from the internal message queue.

Syntax

ANSI (Cross Platform)
int DoEvents();

Unicode (Windows)
INT DoEvents();

int ipworks_udp_doevents(void* lpObj);

int DoEvents();

Remarks

When DoEvents is called, the class processes any available events. If no events are available, it waits for a preset period of time, and then returns.

Error Handling (C++)

This method returns a result code; 0 indicates success, while a non-zero error code indicates that this method encountered an error during its execution. If an error occurs, the GetLastError() method can be called to retrieve the associated error message. (Note: This method's result code can also be obtained by calling the GetLastErrorCode() method after it returns.)

PauseData Method (UDP Class)

This method pauses data reception.

Syntax

ANSI (Cross Platform)
int PauseData();

Unicode (Windows)
INT PauseData();

int ipworks_udp_pausedata(void* lpObj);

int PauseData();

Remarks

This method pauses data reception when called. While data reception is paused, the DataIn event will not fire. Call ProcessData to reenable data reception.

Error Handling (C++)

This method returns a result code; 0 indicates success, while a non-zero error code indicates that this method encountered an error during its execution. If an error occurs, the GetLastError() method can be called to retrieve the associated error message. (Note: This method's result code can also be obtained by calling the GetLastErrorCode() method after it returns.)

ProcessData Method (UDP Class)

This method reenables data reception after a call to PauseData .

Syntax

ANSI (Cross Platform)
int ProcessData();

Unicode (Windows)
INT ProcessData();

int ipworks_udp_processdata(void* lpObj);

int ProcessData();

Remarks

This method reenables data reception after a previous call to PauseData. When PauseData is called, the DataIn event will not fire. To reenable data reception and allow DataIn to fire, call this method.

Note: This method is used only after previously calling PauseData. It does not need to be called to process incoming data by default.

Error Handling (C++)

This method returns a result code; 0 indicates success, while a non-zero error code indicates that this method encountered an error during its execution. If an error occurs, the GetLastError() method can be called to retrieve the associated error message. (Note: This method's result code can also be obtained by calling the GetLastErrorCode() method after it returns.)

Reset Method (UDP Class)

Reset the class.

Syntax

ANSI (Cross Platform)
int Reset();

Unicode (Windows)
INT Reset();

int ipworks_udp_reset(void* lpObj);

int Reset();

Remarks

This method will reset the class's properties to their default values.

Error Handling (C++)

This method returns a result code; 0 indicates success, while a non-zero error code indicates that this method encountered an error during its execution. If an error occurs, the GetLastError() method can be called to retrieve the associated error message. (Note: This method's result code can also be obtained by calling the GetLastErrorCode() method after it returns.)

ResolveRemoteHost Method (UDP Class)

Resolves the hostname in RemoteHost to an IP address.

Syntax

ANSI (Cross Platform)
int ResolveRemoteHost();

Unicode (Windows)
INT ResolveRemoteHost();

int ipworks_udp_resolveremotehost(void* lpObj);

int ResolveRemoteHost();

Remarks

This method resolves the hostname specified by RemoteHost to an IP address. The resolved value is available in the RemoteHost property after this method returns.

In most cases calling this method is not necessary, the class will resolve the hostname automatically when necessary. If DelayHostResolution is true this method may be called to manually resolve RemoteHost if desired.

Error Handling (C++)

This method returns a result code; 0 indicates success, while a non-zero error code indicates that this method encountered an error during its execution. If an error occurs, the GetLastError() method can be called to retrieve the associated error message. (Note: This method's result code can also be obtained by calling the GetLastErrorCode() method after it returns.)

Send Method (UDP Class)

Send data to the remote host.

Syntax

ANSI (Cross Platform)
int Send(const char* lpText, int lenText);

Unicode (Windows)
INT Send(LPCSTR lpText, INT lenText);

int ipworks_udp_send(void* lpObj, const char* lpText, int lenText);

int Send(QByteArray qbaText);

Remarks

Calling this method is equivalent to setting the DataToSend property to Text.

Example (Send Data)

UDPControl.LocalPort = 8765 UDPControl.RemotePort = 8765 UDPControl.RemoteHost = "HostNameOrIPAddress" UDPControl.Active = True UDPControl.Send("Hello!")

Error Handling (C++)

This method returns a result code; 0 indicates success, while a non-zero error code indicates that this method encountered an error during its execution. If an error occurs, the GetLastError() method can be called to retrieve the associated error message. (Note: This method's result code can also be obtained by calling the GetLastErrorCode() method after it returns.)

SendBytes Method (UDP Class)

Send data to the remote host.

Syntax

ANSI (Cross Platform)
int SendBytes(const char* lpData, int lenData);

Unicode (Windows)
INT SendBytes(LPCSTR lpData, INT lenData);

int ipworks_udp_sendbytes(void* lpObj, const char* lpData, int lenData);

int SendBytes(QByteArray qbaData);

Remarks

Calling this method is equivalent to call SendBytes/SendText method.

Example (Send Data)

UDPControl.LocalPort = 8765 UDPControl.RemotePort = 8765 UDPControl.RemoteHost = "HostNameOrIPAddress" UDPControl.Active = True UDPControl.Send("Hello!")

Error Handling (C++)

This method returns a result code; 0 indicates success, while a non-zero error code indicates that this method encountered an error during its execution. If an error occurs, the GetLastError() method can be called to retrieve the associated error message. (Note: This method's result code can also be obtained by calling the GetLastErrorCode() method after it returns.)

SendText Method (UDP Class)

Send data to the remote host.

Syntax

ANSI (Cross Platform)
int SendText(const char* lpszText);

Unicode (Windows)
INT SendText(LPCWSTR lpszText);

int ipworks_udp_sendtext(void* lpObj, const char* lpszText);

int SendText(const QString& qsText);

Remarks

Calling this method is equivalent to call SendBytes/SendText method.

Example (Send Data)

UDPControl.LocalPort = 8765 UDPControl.RemotePort = 8765 UDPControl.RemoteHost = "HostNameOrIPAddress" UDPControl.Active = True UDPControl.Send("Hello!")

Error Handling (C++)

This method returns a result code; 0 indicates success, while a non-zero error code indicates that this method encountered an error during its execution. If an error occurs, the GetLastError() method can be called to retrieve the associated error message. (Note: This method's result code can also be obtained by calling the GetLastErrorCode() method after it returns.)

DataIn Event (UDP Class)

Fired when data is received.

Syntax

ANSI (Cross Platform)
virtual int FireDataIn(UDPDataInEventParams *e);

typedef struct {
  const char *Datagram;
  int lenDatagram;
  const char *SourceAddress;
  int SourcePort;
  int reserved;
} UDPDataInEventParams;


Unicode (Windows)
virtual INT FireDataIn(UDPDataInEventParams *e);

typedef struct {
  LPCSTR Datagram;
  INT lenDatagram;
  LPCWSTR SourceAddress;
  INT SourcePort;
  INT reserved;
} UDPDataInEventParams;

#define EID_UDP_DATAIN 1

virtual INT IPWORKS_CALL FireDataIn(LPSTR &lpDatagram, INT &lenDatagram, LPSTR &lpszSourceAddress, INT &iSourcePort);

class UDPDataInEventParams {
public:
  const QByteArray &Datagram();

  const QString &SourceAddress();

  int SourcePort();

  int EventRetVal();
  void SetEventRetVal(int iRetVal);
};

// To handle, connect one or more slots to this signal.
void DataIn(UDPDataInEventParams *e);

// Or, subclass UDP and override this emitter function.
virtual int FireDataIn(UDPDataInEventParams *e) {...}

Remarks

The DataIn event is fired every time a new datagram is received.

Datagram contains the packet as sent by the remote host.

SourceAddress contains the IP number (Internet address) of the remote host, and SourcePort contains the port from which the packet originated.

Note: Events are not re-entrant. Performing time-consuming operations within this event will prevent it from firing again in a timely manner and may affect overall performance.

Error Event (UDP Class)

Information about errors during data delivery.

Syntax

ANSI (Cross Platform)
virtual int FireError(UDPErrorEventParams *e);

typedef struct {
  int ErrorCode;
  const char *Description;
  int reserved;
} UDPErrorEventParams;


Unicode (Windows)
virtual INT FireError(UDPErrorEventParams *e);

typedef struct {
  INT ErrorCode;
  LPCWSTR Description;
  INT reserved;
} UDPErrorEventParams;

#define EID_UDP_ERROR 2

virtual INT IPWORKS_CALL FireError(INT &iErrorCode, LPSTR &lpszDescription);

class UDPErrorEventParams {
public:
  int ErrorCode();

  const QString &Description();

  int EventRetVal();
  void SetEventRetVal(int iRetVal);
};

// To handle, connect one or more slots to this signal.
void Error(UDPErrorEventParams *e);

// Or, subclass UDP and override this emitter function.
virtual int FireError(UDPErrorEventParams *e) {...}

Remarks

The Error event is fired in case of exceptional conditions during message processing. Normally the class fails with an error.

ErrorCode contains an error code and Description contains a textual description of the error. For a list of valid error codes and their descriptions, please refer to the Error Codes section.

ReadyToSend Event (UDP Class)

Fired when the class is ready to send data.

Syntax

ANSI (Cross Platform)
virtual int FireReadyToSend(UDPReadyToSendEventParams *e);

typedef struct {
  int reserved;
} UDPReadyToSendEventParams;


Unicode (Windows)
virtual INT FireReadyToSend(UDPReadyToSendEventParams *e);

typedef struct {
  INT reserved;
} UDPReadyToSendEventParams;

#define EID_UDP_READYTOSEND 3

virtual INT IPWORKS_CALL FireReadyToSend();

class UDPReadyToSendEventParams {
public:
  int EventRetVal();
  void SetEventRetVal(int iRetVal);
};

// To handle, connect one or more slots to this signal.
void ReadyToSend(UDPReadyToSendEventParams *e);

// Or, subclass UDP and override this emitter function.
virtual int FireReadyToSend(UDPReadyToSendEventParams *e) {...}

Remarks

The ReadyToSend event indicates that the underlying TCP/IP subsystem is ready to accept data after a failed DataToSend.

Config Settings (UDP Class)

The class accepts one or more of the following configuration settings. Configuration settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the class, access to these internal properties is provided through the Config method.

UDP Config Settings

CaptureIPPacketInfo:   Used to capture the packet information.

If this is set to true, the component will capture the IP packet information.

The default value for this setting is False.

Note: This setting is only available in Windows.

DelayHostResolution:   Whether the hostname is resolved when RemoteHost is set.

This setting specifies whether a hostname is resolved immediately when RemoteHost is set. If true the class will resolve the hostname and the IP address will be present in the RemoteHost property. If false, the hostname is not resolved until needed by the component when a method to connect or send data is called. If desired, ResolveRemoteHost may called to manually resolve the value in RemoteHost at any time.

The default value is false.

DestinationAddress:   Used to get the destination address from the packet information.

If CaptureIPPacketInfo is set to true, then this will be populated with the packet's destination address when a packet is received. This information will be accessible in the DataIn event.

Note: This setting is only available in Windows.

DontFragment:   Used to set the Don't Fragment flag of outgoing packets.

When set to True, packets sent by the class will have the Don't Fragment flag set. The default value is False.

LocalHost:   The name of the local host through which connections are initiated or accepted.

The LocalHost setting contains the name of the local host as obtained by the gethostname() system call, or if the user has assigned an IP address, the value of that address.

In multi-homed hosts (machines with more than one IP interface) setting LocalHost to the value of an interface will make the class initiate connections (or accept in the case of server classs) only through that interface.

If the class is connected, the LocalHost setting shows the IP address of the interface through which the connection is made in internet dotted format (aaa.bbb.ccc.ddd). In most cases, this is the address of the local host, except for multi-homed hosts (machines with more than one IP interface).

LocalPort:   The port in the local host where the class binds.

This must be set before a connection is attempted. It instructs the class to bind to a specific port (or communication endpoint) in the local machine.

Setting this to 0 (default) enables the system to choose a port at random. The chosen port will be shown by LocalPort after the connection is established.

LocalPort cannot be changed once a connection is made. Any attempt to set this when a connection is active will generate an error.

This; setting is useful when trying to connect to services that require a trusted port in the client side. An example is the remote shell (rsh) service in UNIX systems.

MaxPacketSize:   The maximum length of the packets that can be received.

This setting specifies the maximum size of the datagrams that the class will accept without truncation.

QOSDSCPValue:   Used to specify an arbitrary QOS/DSCP setting (optional).

UseConnection must be True to use this setting. This option allows you to specify an arbitrary DSCP value between 0 and 63. The default is 0. When set to the default value the component will not set a DSCP value.

Note: This setting uses the qWAVE API is only available on Windows 7, Windows Server 2008 R2, and later.

QOSTrafficType:   Used to specify QOS/DSCP settings (optional).

UseConnection must be True to use this setting. You may specify either the text or integer values: BestEffort (0), Background (1), ExcellentEffort (2), AudioVideo (3), Voice (4), and Control (5).

Note: This setting uses the qWAVE API which is only available on Windows Vista and Windows Server 2008 or above.

Note: QOSTrafficType must be set before setting Active to true.

ShareLocalPort:   If set to True, allows more than one instance of the class to be active on the same local port.

This option must be set before the class is activated through the Active property or it will have no effect.

The default value for this setting is False.

SourceIPAddress:   Used to set the source IP address used when sending a packet.

This configuration setting can be used to override the source IP address when sending a packet.

Note: This setting is only available in Windows and requires that the winpcap library be installed (or npcap with winpcap compatibility).

SourceMacAddress:   Used to set the source MAC address used when sending a packet.

This configuration setting can be used to override the source MAC address when sending a packet.

Note: This setting is only available in Windows and requires that the winpcap library be installed (or npcap with winpcap compatibility).

UseConnection:   Determines whether to use a connected socket.

UseConnection specifies whether the class should use a connected socket or not. The connection is defined as an association in between the local address/port and the remote address/port. As such, this is not a connection in the traditional TCP sense. What it means is only that the class will send and receive data only to and from the specified destination.

The default value for this setting is False.

UseIPv6:   Whether or not to use IPv6.

By default, the component expects an IPv4 address for local and remote host properties, and will create an IPv4 socket. To use IPv6 instead, set this to True.

Socket Config Settings

AbsoluteTimeout:   Determines whether timeouts are inactivity timeouts or absolute timeouts.

If AbsoluteTimeout is set to True, any method which does not complete within Timeout seconds will be aborted. By default, AbsoluteTimeout is False, and the timeout is an inactivity timeout.

Note: This option is not valid for UDP ports.

FirewallData:   Used to send extra data to the firewall.

When the firewall is a tunneling proxy, use this property to send custom (additional) headers to the firewall (e.g. headers for custom authentication schemes).

InBufferSize:   The size in bytes of the incoming queue of the socket.

This is the size of an internal queue in the TCP/IP stack. You can increase or decrease its size depending on the amount of data that you will be receiving. Increasing the value of the InBufferSize setting can provide significant improvements in performance in some cases.

Some TCP/IP implementations do not support variable buffer sizes. If that is the case, when the class is activated the InBufferSize reverts to its defined size. The same happens if you attempt to make it too large or too small.

OutBufferSize:   The size in bytes of the outgoing queue of the socket.

This is the size of an internal queue in the TCP/IP stack. You can increase or decrease its size depending on the amount of data that you will be sending. Increasing the value of the OutBufferSize setting can provide significant improvements in performance in some cases.

Some TCP/IP implementations do not support variable buffer sizes. If that is the case, when the class is activated the OutBufferSize reverts to its defined size. The same happens if you attempt to make it too large or too small.

Base Config Settings

BuildInfo:   Information about the product's build.

When queried, this setting will return a string containing information about the product's build.

CodePage:   The system code page used for Unicode to Multibyte translations.

The default code page is Unicode UTF-8 (65001).

The following is a list of valid code page identifiers:

IdentifierName
037IBM EBCDIC - U.S./Canada
437OEM - United States
500IBM EBCDIC - International
708Arabic - ASMO 708
709Arabic - ASMO 449+, BCON V4
710Arabic - Transparent Arabic
720Arabic - Transparent ASMO
737OEM - Greek (formerly 437G)
775OEM - Baltic
850OEM - Multilingual Latin I
852OEM - Latin II
855OEM - Cyrillic (primarily Russian)
857OEM - Turkish
858OEM - Multilingual Latin I + Euro symbol
860OEM - Portuguese
861OEM - Icelandic
862OEM - Hebrew
863OEM - Canadian-French
864OEM - Arabic
865OEM - Nordic
866OEM - Russian
869OEM - Modern Greek
870IBM EBCDIC - Multilingual/ROECE (Latin-2)
874ANSI/OEM - Thai (same as 28605, ISO 8859-15)
875IBM EBCDIC - Modern Greek
932ANSI/OEM - Japanese, Shift-JIS
936ANSI/OEM - Simplified Chinese (PRC, Singapore)
949ANSI/OEM - Korean (Unified Hangul Code)
950ANSI/OEM - Traditional Chinese (Taiwan; Hong Kong SAR, PRC)
1026IBM EBCDIC - Turkish (Latin-5)
1047IBM EBCDIC - Latin 1/Open System
1140IBM EBCDIC - U.S./Canada (037 + Euro symbol)
1141IBM EBCDIC - Germany (20273 + Euro symbol)
1142IBM EBCDIC - Denmark/Norway (20277 + Euro symbol)
1143IBM EBCDIC - Finland/Sweden (20278 + Euro symbol)
1144IBM EBCDIC - Italy (20280 + Euro symbol)
1145IBM EBCDIC - Latin America/Spain (20284 + Euro symbol)
1146IBM EBCDIC - United Kingdom (20285 + Euro symbol)
1147IBM EBCDIC - France (20297 + Euro symbol)
1148IBM EBCDIC - International (500 + Euro symbol)
1149IBM EBCDIC - Icelandic (20871 + Euro symbol)
1200Unicode UCS-2 Little-Endian (BMP of ISO 10646)
1201Unicode UCS-2 Big-Endian
1250ANSI - Central European
1251ANSI - Cyrillic
1252ANSI - Latin I
1253ANSI - Greek
1254ANSI - Turkish
1255ANSI - Hebrew
1256ANSI - Arabic
1257ANSI - Baltic
1258ANSI/OEM - Vietnamese
1361Korean (Johab)
10000MAC - Roman
10001MAC - Japanese
10002MAC - Traditional Chinese (Big5)
10003MAC - Korean
10004MAC - Arabic
10005MAC - Hebrew
10006MAC - Greek I
10007MAC - Cyrillic
10008MAC - Simplified Chinese (GB 2312)
10010MAC - Romania
10017MAC - Ukraine
10021MAC - Thai
10029MAC - Latin II
10079MAC - Icelandic
10081MAC - Turkish
10082MAC - Croatia
12000Unicode UCS-4 Little-Endian
12001Unicode UCS-4 Big-Endian
20000CNS - Taiwan
20001TCA - Taiwan
20002Eten - Taiwan
20003IBM5550 - Taiwan
20004TeleText - Taiwan
20005Wang - Taiwan
20105IA5 IRV International Alphabet No. 5 (7-bit)
20106IA5 German (7-bit)
20107IA5 Swedish (7-bit)
20108IA5 Norwegian (7-bit)
20127US-ASCII (7-bit)
20261T.61
20269ISO 6937 Non-Spacing Accent
20273IBM EBCDIC - Germany
20277IBM EBCDIC - Denmark/Norway
20278IBM EBCDIC - Finland/Sweden
20280IBM EBCDIC - Italy
20284IBM EBCDIC - Latin America/Spain
20285IBM EBCDIC - United Kingdom
20290IBM EBCDIC - Japanese Katakana Extended
20297IBM EBCDIC - France
20420IBM EBCDIC - Arabic
20423IBM EBCDIC - Greek
20424IBM EBCDIC - Hebrew
20833IBM EBCDIC - Korean Extended
20838IBM EBCDIC - Thai
20866Russian - KOI8-R
20871IBM EBCDIC - Icelandic
20880IBM EBCDIC - Cyrillic (Russian)
20905IBM EBCDIC - Turkish
20924IBM EBCDIC - Latin-1/Open System (1047 + Euro symbol)
20932JIS X 0208-1990 & 0121-1990
20936Simplified Chinese (GB2312)
21025IBM EBCDIC - Cyrillic (Serbian, Bulgarian)
21027Extended Alpha Lowercase
21866Ukrainian (KOI8-U)
28591ISO 8859-1 Latin I
28592ISO 8859-2 Central Europe
28593ISO 8859-3 Latin 3
28594ISO 8859-4 Baltic
28595ISO 8859-5 Cyrillic
28596ISO 8859-6 Arabic
28597ISO 8859-7 Greek
28598ISO 8859-8 Hebrew
28599ISO 8859-9 Latin 5
28605ISO 8859-15 Latin 9
29001Europa 3
38598ISO 8859-8 Hebrew
50220ISO 2022 Japanese with no halfwidth Katakana
50221ISO 2022 Japanese with halfwidth Katakana
50222ISO 2022 Japanese JIS X 0201-1989
50225ISO 2022 Korean
50227ISO 2022 Simplified Chinese
50229ISO 2022 Traditional Chinese
50930Japanese (Katakana) Extended
50931US/Canada and Japanese
50933Korean Extended and Korean
50935Simplified Chinese Extended and Simplified Chinese
50936Simplified Chinese
50937US/Canada and Traditional Chinese
50939Japanese (Latin) Extended and Japanese
51932EUC - Japanese
51936EUC - Simplified Chinese
51949EUC - Korean
51950EUC - Traditional Chinese
52936HZ-GB2312 Simplified Chinese
54936Windows XP: GB18030 Simplified Chinese (4 Byte)
57002ISCII Devanagari
57003ISCII Bengali
57004ISCII Tamil
57005ISCII Telugu
57006ISCII Assamese
57007ISCII Oriya
57008ISCII Kannada
57009ISCII Malayalam
57010ISCII Gujarati
57011ISCII Punjabi
65000Unicode UTF-7
65001Unicode UTF-8

The following is a list of valid code page identifiers for Mac OS only:

IdentifierName
1ASCII
2NEXTSTEP
3JapaneseEUC
4UTF8
5ISOLatin1
6Symbol
7NonLossyASCII
8ShiftJIS
9ISOLatin2
10Unicode
11WindowsCP1251
12WindowsCP1252
13WindowsCP1253
14WindowsCP1254
15WindowsCP1250
21ISO2022JP
30MacOSRoman
10UTF16String
0x90000100UTF16BigEndian
0x94000100UTF16LittleEndian
0x8c000100UTF32String
0x98000100UTF32BigEndian
0x9c000100UTF32LittleEndian
65536Proprietary
LicenseInfo:   Information about the current license.

When queried, this setting will return a string containing information about the license this instance of a class is using. It will return the following information:

  • Product: The product the license is for.
  • Product Key: The key the license was generated from.
  • License Source: Where the license was found (e.g., RuntimeLicense, License File).
  • License Type: The type of license installed (e.g., Royalty Free, Single Server).
  • Last Valid Build: The last valid build number for which the license will work.
ProcessIdleEvents:   Whether the class uses its internal event loop to process events when the main thread is idle.

If set to False, the class will not fire internal idle events. Set this to False to use the class in a background thread on Mac OS. By default, this setting is True.

SelectWaitMillis:   The length of time in milliseconds the class will wait when DoEvents is called if there are no events to process.

If there are no events to process when DoEvents is called, the class will wait for the amount of time specified here before returning. The default value is 20.

UseInternalSecurityAPI:   Tells the class whether or not to use the system security libraries or an internal implementation.

By default the class will use the system security libraries to perform cryptographic functions where applicable. Setting this to true tells the class to use the internal implementation instead of using the system's security API.

Trappable Errors (UDP Class)

Error Handling (C++)

Call the GetLastErrorCode() method to obtain the last called method's result code; 0 indicates success, while a non-zero error code indicates that this method encountered an error during its execution. Known error codes are listed below. If an error occurs, the GetLastError() method can be called to retrieve the associated error message.

UDP Errors

104   UDP is already Active.
106   You cannot change the LocalPort while the class is Active.
107   You cannot change the LocalHost at this time. A connection is in progress.
109   The class must be Active for this operation.
112   Cannot change MaxPacketSize while the class is Active.
113   Cannot change ShareLocalPort option while the class is Active.
114   Cannot change RemoteHost when UseConnection is set and the class Active.
115   Cannot change RemotePort when UseConnection is set and the class is Active.
116   RemotePort can't be zero when UseConnection is set. Please specify a valid service port number.
117   Cannot change UseConnection while the class is Active.
118   Message can't be longer than MaxPacketSize.
119   Message too short.
434   Unable to convert string to selected CodePage

SSL Errors

270   Cannot load specified security library.
271   Cannot open certificate store.
272   Cannot find specified certificate.
273   Cannot acquire security credentials.
274   Cannot find certificate chain.
275   Cannot verify certificate chain.
276   Error during handshake.
280   Error verifying certificate.
281   Could not find client certificate.
282   Could not find server certificate.
283   Error encrypting data.
284   Error decrypting data.

TCP/IP Errors

10004   [10004] Interrupted system call.
10009   [10009] Bad file number.
10013   [10013] Access denied.
10014   [10014] Bad address.
10022   [10022] Invalid argument.
10024   [10024] Too many open files.
10035   [10035] Operation would block.
10036   [10036] Operation now in progress.
10037   [10037] Operation already in progress.
10038   [10038] Socket operation on non-socket.
10039   [10039] Destination address required.
10040   [10040] Message too long.
10041   [10041] Protocol wrong type for socket.
10042   [10042] Bad protocol option.
10043   [10043] Protocol not supported.
10044   [10044] Socket type not supported.
10045   [10045] Operation not supported on socket.
10046   [10046] Protocol family not supported.
10047   [10047] Address family not supported by protocol family.
10048   [10048] Address already in use.
10049   [10049] Can't assign requested address.
10050   [10050] Network is down.
10051   [10051] Network is unreachable.
10052   [10052] Net dropped connection or reset.
10053   [10053] Software caused connection abort.
10054   [10054] Connection reset by peer.
10055   [10055] No buffer space available.
10056   [10056] Socket is already connected.
10057   [10057] Socket is not connected.
10058   [10058] Can't send after socket shutdown.
10059   [10059] Too many references, can't splice.
10060   [10060] Connection timed out.
10061   [10061] Connection refused.
10062   [10062] Too many levels of symbolic links.
10063   [10063] File name too long.
10064   [10064] Host is down.
10065   [10065] No route to host.
10066   [10066] Directory not empty
10067   [10067] Too many processes.
10068   [10068] Too many users.
10069   [10069] Disc Quota Exceeded.
10070   [10070] Stale NFS file handle.
10071   [10071] Too many levels of remote in path.
10091   [10091] Network subsystem is unavailable.
10092   [10092] WINSOCK DLL Version out of range.
10093   [10093] Winsock not loaded yet.
11001   [11001] Host not found.
11002   [11002] Non-authoritative 'Host not found' (try again or check DNS setup).
11003   [11003] Non-recoverable errors: FORMERR, REFUSED, NOTIMP.
11004   [11004] Valid name, no data record (check DNS setup).

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IPWorks 2022 C++ Edition - Version 22.0 [Build 8369]