0x12 C12PacketUpdateSign
Player finishes editing a sign. Sends the block position and four lines of text as IChatComponents.
Fields
| Field | Type | Description |
|---|---|---|
| position | BlockPos | Sign block position |
| lines | IChatComponent[4] | 4 lines of sign text as JSON ChatComponents |
Wire Encoding
| Field | Type | Notes |
|---|---|---|
| Position | Position (long) | BlockPos encoded as long |
| Line 1 | Chat Component (JSON) | Sign line 1 |
| Line 2 | Chat Component (JSON) | Sign line 2 |
| Line 3 | Chat Component (JSON) | Sign line 3 |
| Line 4 | Chat Component (JSON) | Sign line 4 |
MCP References
MCP
NetHandlerPlayServer.processUpdateSign()Handler Interface
HND
INetHandlerPlayServerNotes
Jigsaw 0.26 OPSign module cancels and resends C12 twice to crash the server's sign data structure on vanilla 1.8-1.8.5 servers (exploit patched in 1.8.8+).
implementation Implementation Cases
SignEditor
Send sign text to server after editing.
ColorSigns
Send sign text to server after editing.