Internet Direct (Indy) Version 9.0.2 Beta
TIdMessageDecoderInfo.CheckForStart
Specifies a method for retrieving a decoder class instance, and associating the decoder with a given message.

function CheckForStart(ASender: TIdMessage; ALine: string): TIdMessageDecoder; virtual; abstract;
Parameters
ASender: TIdMessage
Message associated with the decoder instance.

ALine: string
Encoded message part content to be examined to determine the appropriate decoder class.

Returns
TIdMessageDecoder - Decoder class instance to use for the message part.

Description
CheckForStart is an abstract virtual function in TIdMessageDecoderInfo that specifies a method for retrieving a decoder class instance, and associating the decoder class instance with a specific message.

ASender is the TIdMessage to be associated with the decoder class instance.

ALine is a line from the message part that will be examined to determine if the registered decoder can be used for decoding the message part.

Descendant classes, like TIdMessageDecoderInfoMIME, TIdMessageDecoderInfoUUE, and TIdMessageDecoderInfoXXE must implement comparisons to determine if ALine contains a marker signifying the start of a block using the specific encoding algorithm. If ALine contains the appropriate signature, a message decoder instance is created for ASender in the function return value. Otherwise the function return value is Nil.