Ancestor for platform-specific protocol stack interfaces.

TIdStack = class

TIdStack is an ancestor class for platform-specific protocol stack interfaces. This class is created and destroyed as needed. This is mentioned only because there a few useful low-level properties and methods.

Indicates the error number encounterd in a protocol stack operation.

property LastError: Integer;

Integer - numeric error number from the protocol stack.

LastError is a read-only Integer property that indicates a previous return value from a protocol stack operation with the value Id_SOCKET_ERROR. LastError is updated in CheckForSocketError to contain the numeric result from WSGetLastError. LastError is generally used when the stack instance needs to call RaiseSocketError after encountering an error that is not handled by the protocol stack.

Identifies the Host name or address for the local computer.

property LocalAddress: string;

LocalAddress is a read-only String property that contains the current host name or address. Use LocalAddresses to access all names or addresses assigned to the local computer.

List of host names for the local computer.

property LocalAddresses: TStrings;

LocalAddresses is a read-only TStrings property that is a list of all host names or IP addresses assigned for the local computer. Use LocalAddress to access the current host name or IP address for the local computer.

Performs a check for specific socket error numbers.

function CheckForSocketError(const AResult: integer = Id_SOCKET_ERROR): boolean; overload;
function CheckForSocketError(const AResult: integer; const AIgnore: array of integer): boolean; overload;

Error number to ne checked. Default value is Id_SOCKET_ERROR.

An array of inter socket error numbers to be ignored.

Boolean - True when a the last error is ignored.

CheckForSocketError is a Boolean function used to perform a check for specific socket error numbers. When AResult does not contain Id_SOCKET_ERROR or AIgnore is an empty array, all socket errors are detected.

If the last socket error is contained in AIgnore, the return value is True. Under all other conditions the return values is False. If a socket error si detected and not ignored, RaiseSocketError is called with the socket error number detected.

Performs a check for specific socket error numbers.

function CheckForSocketError(const AResult: integer = Id_SOCKET_ERROR): boolean; overload;
function CheckForSocketError(const AResult: integer; const AIgnore: array of integer): boolean; overload;

Error number to ne checked. Default value is Id_SOCKET_ERROR.

An array of inter socket error numbers to be ignored.

Boolean - True when a the last error is ignored.

CheckForSocketError is a Boolean function used to perform a check for specific socket error numbers. When AResult does not contain Id_SOCKET_ERROR or AIgnore is an empty array, all socket errors are detected.

If the last socket error is contained in AIgnore, the return value is True. Under all other conditions the return values is False. If a socket error si detected and not ignored, RaiseSocketError is called with the socket error number detected.

Constructor for the object instance.

constructor Create; virtual; reintroduce;

Create is the constructor for the object instance. Create is an abstract method that must be overridden in descendant classes to provide any initialization sequences before using stack functions.

Creates a new socket descriptor.

function CreateSocketHandle(const ASocketType: Integer; const AProtocol: Integer = Id_IPPROTO_IP): TIdStackSocketHandle;

Socket type for the descriptor.

Protocol family for the descriptor. Default value is Id_IPPROTO_IP.

TIdStackSocketHandle - Newly created socket descriptor.

CreateSocketHandle is a TIdStackSocketHandle function that create a new socket descriptor using the socket type specifies in AScoketType and the protocol family specified in AProtocol.

On the Windows platform, CreateSocketHandle calls the WSSocket function. If an error occurs while creating the new socket descriptor, an EIdInvalidSocket exception is raised.

Get a platform-specific protocol stack instance.

class function CreateStack: TIdStack;

CreateStack is a TIdStack class function that returns a TIdStack descendant for a specific platform. This is an internal procedure called by Indy and should not be used directly in an application.

Frees the object instance.

destructor Destroy; override;

Destroy is the destructor for the object instance, and is overridden in descendant classes to provide any needed shut-down required for the protocol stack.

Detects a numeric IP address.

function IsIP(AIP: string): boolean;

Host name or IP address to be checked.

Boolean - True if the parameter is a numeric IP address.

IsIP is a Boolean function that returns True if the string in AIP is a numeric IP address, or False if AIP contains a host name.

For example, if the value "129.71.2.4" is passed as AIP, this function will return True. If the value "wvnvm.wvnet.edu" is passed in AIP, this function will return False.

Creates an exception for a socket error number.

procedure RaiseSocketError(const AErr: integer);

Socket error number to be raised.

RaiseSocketError is a procedure that raises an EIdSocketError exception. RaiseSocketError uses the error code specified by the AErr integer parameter as the LastError parameter, and the translated socket error message for the AErr integer value.

Note: It is normal to receive a 10038 exception (10038, NOT others!) here when *shutting down* (NOT at other times!) servers (NOT clients!). If you receive a 10038 exception here please see the FAQ at http://www.nevrona.com/Indy/FAQ.html

If you DID read the FAQ and have further questions, please feel free to ask using one of the methods (Carefully note that these methods do not include email) listed on the Tech Support link at http://www.nevrona.com/Indy

Convert a host name into an IP address.

function ResolveHost(const AHost: string): string;

Host name to convert.

String - IP address for the host name.

ResolveHost is a String function that returns the IP address for a given host name specified by the AHost parameter. For example, if AHost is set to "wvnvm.wvnet.edu", the function will return "129.71.2.4". If AHost was set to 129.71.2.4", this function returns "129.71.2.4".

Converts an string into a structured IP address.

function StringToTInAddr(AIP: string): TIdInAddr;

IP address string to be converted.

TIdInAddr - IP address structure.

StringToTInAddr is a TIdInAddr function that returns a structure containing the IP Address specified by the AIP parameter. This function is used Internally in Indy.

Converts an IP structure to a string.

function TInAddrToString(var AInAddr): string; virtual; abstract;

IP address structure to convert.

String - String containing the converted IP address.

TInAddrToString is a String function that returns an IP address as a string from a TInAddr structure. This is used internally in Indy so you do not call this directly.

Translates a string a creates an IP address structure.

procedure TranslateStringToTInAddr(AIP: string; var AInAddr); virtual; abstract;

String to be translated and converted.

IP address structure for the converted value.

TranslateStringToTInAddr that translates an IP address from the string parameter AIP and returns it in the TInAddr specified by the AInAddr parameter. This is used internally in Indy so you do not call this directly.

function WSAccept(ASocket: TIdStackSocketHandle; var VIP: string; var VPort: Integer): TIdStackSocketHandle; virtual; abstract;

WSAccept

function WSBind(ASocket: TIdStackSocketHandle; const AFamily: Integer; const AIP: string; const APort: Integer): Integer; virtual; abstract;

WSBind

function WSCloseSocket(ASocket: TIdStackSocketHandle): Integer; virtual; abstract;

WSCloseSocket

function WSConnect(const ASocket: TIdStackSocketHandle; const AFamily: Integer; const AIP: string; const APort: Integer): Integer; virtual; abstract;

WSConnect

function WSGetHostByAddr(const AAddress: string): string; virtual; abstract;

WSGetHostByAddr

function WSGetHostByName(const AHostName: string): string; virtual; abstract;

WSGetHostByName

function WSGetHostName: string; virtual; abstract;

WSGetHostName

function WSGetLastError: Integer; virtual; abstract;

WSGetLastError

procedure WSGetPeerName(ASocket: TIdStackSocketHandle; var AFamily: Integer; var AIP: string; var APort: Integer); virtual; abstract;

WSGetPeerName

function WSGetServByName(const AServiceName: string): Integer; virtual; abstract;

WSGetServByName

function WSGetServByPort(const APortNumber: Integer): TStrings; virtual; abstract;

WSGetServByPort

procedure WSGetSockName(ASocket: TIdStackSocketHandle; var AFamily: Integer; var AIP: string; var APort: Integer); virtual; abstract;

WSGetSockName

function WSGetSockOpt(ASocket: TIdStackSocketHandle; Alevel: Integer; AOptname: Integer; AOptval: PChar; var AOptlen: Integer): Integer; virtual; abstract;

WSGetSockOpt

function WSHToNL(AHostLong: LongWord): LongWord; virtual; abstract;

WSHToNL

function WSHToNs(AHostShort: Word): Word; virtual; abstract;

WSHToNs

function WSListen(ASocket: TIdStackSocketHandle; ABackLog: Integer): Integer; virtual; abstract;

WSListen

function WSNToHL(ANetLong: LongWord): LongWord; virtual; abstract;

WSNToHL

function WSNToHs(ANetShort: Word): Word; virtual; abstract;

WSNToHs

function WSRecv(ASocket: TIdStackSocketHandle; var ABuffer; const ABufferLength: Integer; const AFlags: Integer): Integer; virtual; abstract;

WSRecv

function WSRecvFrom(const ASocket: TIdStackSocketHandle; var ABuffer; const ALength: Integer; const AFlags: Integer; var VIP: string; var VPort: Integer): Integer; virtual; abstract;

WSRecvFrom

function WSSelect(ARead: TList; AWrite: TList; AErrors: TList; ATimeout: Integer): Integer; virtual; abstract;

WSSelect

function WSSend(ASocket: TIdStackSocketHandle; var ABuffer; const ABufferLength: Integer; const AFlags: Integer): Integer; virtual; abstract;

WSSend

function WSSendTo(ASocket: TIdStackSocketHandle; var ABuffer; const ABufferLength: Integer; const AFlags: Integer; const AIP: string; const APort: integer): Integer; virtual; abstract;

WSSendTo

function WSSetSockOpt(ASocket: TIdStackSocketHandle; ALevel: Integer; AOptName: Integer; AOptVal: PChar; AOptLen: Integer): Integer; virtual; abstract;

WSSetSockOpt

function WSShutdown(ASocket: TIdStackSocketHandle; AHow: Integer): Integer; virtual; abstract;

WSShutdown

function WSSocket(AFamily: Integer; AStruct: Integer; AProtocol: Integer): TIdStackSocketHandle; virtual; abstract;

WSSocket

function WSTranslateSocketErrorMsg(const AErr: integer): string; virtual;

WSTranslateSocketErrorMsg