Emoticon
Emoticon
[Cueball sits at computer, typing.] ~!~ Opening Chat with BSLSK05 <NICKM> Hi! <NICKM> A/S/L? <BSLSK05> :) [Cueball looks stunned, flies backward.] [Two smaller frames focus in on BSLSK05's emoticon, implying rotation to show a smile and two open eyes.] [Cueball at computer slouches in chair, dead, crossbones above his head.] [At the remote computer, a basilisk is looking at its screen.]
U+FDD0 did in fact kill at least one chat client at the time. Konversation in particular. (and presumably any other Qt-based chat clients using QTextDocument)
"basically u+fdd0 (eye of basilisk, the snake) is in a char range that's marked for interchange and illegal in utf-8"
"but qt's utf-8 encoder let it through anyway"
"but it just so happens that qt's qtextdocument uses u+fdd0 as text frame delimiter"
"so when you append it to a qtd, counters run wrong and eventually you crash"
"d-bus closes the connection and crashes the client when it encounters illegal utf-8, and kde's notification system works through d-bus"
The problem was fixed after the xkcd "report" and Konversation now handles unicode normally.

A basilisk is a legendary creature reputed to have the power to turn a living creature into stone, killing it with a single glance.
In this comic, Cueball is chatting with a user named 'BSLSK05' ('basilisk05' with the vowels removed) and learns much to his dismay that he is chatting with an actual basilisk, who kills him. It appears that the basilisk's power is fully compatible with the 21st century, and can kill you just with a smiley emoticon over instant messaging.
Cueball's request for A/S/L was a standard question when first meeting someone online; it asks for age, sex (gender), and location .
The title text mentions U+FDD0, claimed to be the character for "eye of the basilisk". In reality this is a code for a "non-character" in Unicode.
[Cueball sits at computer, typing.] ~!~ Opening Chat with BSLSK05 <NICKM> Hi! <NICKM> A/S/L? <BSLSK05> :) [Cueball looks stunned, flies backward.] [Two smaller frames focus in on BSLSK05's emoticon, implying rotation to show a smile and two open eyes.] [Cueball at computer slouches in chair, dead, crossbones above his head.] [At the remote computer, a basilisk is looking at its screen.]
U+FDD0 did in fact kill at least one chat client at the time. Konversation in particular. (and presumably any other Qt-based chat clients using QTextDocument)
"basically u+fdd0 (eye of basilisk, the snake) is in a char range that's marked for interchange and illegal in utf-8"
"but qt's utf-8 encoder let it through anyway"
"but it just so happens that qt's qtextdocument uses u+fdd0 as text frame delimiter"
"so when you append it to a qtd, counters run wrong and eventually you crash"
"d-bus closes the connection and crashes the client when it encounters illegal utf-8, and kde's notification system works through d-bus"
The problem was fixed after the xkcd "report" and Konversation now handles unicode normally.
