Overview:
The talk window provides a third data type for communication in a conference besides audio and video: text strings. Originally implemented as a plug-in to demonstrate and test the Aux Data Transport facilities, it has been integrated into the main application, and the protocol frozen. A talk message consists of a single Aux Data Transport payload of variable length, immediately sent to the recipient(s) upon completion of message entry.
Payload Format:
The talk message actually consists of two sections: a message header, which is typically filled with the user name of the source, and then the message itself. The first is a standard Pascal-style string, which stores its length in the first byte. Appended to this is a C-style string, containing the body of the text message with no length prefix. However, the end of the string is not delimited by a /0 as in conventional C; the end of the aux data payload simply defines the end of the text.
Both messages are in standard ASCII format. All byte characters are permitted (i.e. carriage returns, EOLs, etc...), which may cause formatting problems in the output text field if they are not filtered at either the transmitting or receiving end. No style (bold, italic, etc.) or font information is included.
Example:
If a source client, nicknamed "jef@cornell" originated the message "Hello, world.", the aux data payload would be:
Parsing:
Let us assume that an aux data packet containing a text message has been received and stored in an area of memory at *buffer, of size length.. We wish to access the data by copying it into string.
Either convention can be used and then converted into the other via standard string conversion routines (CtoP, PtoC).