h6. [[Programmer's Reference Manuals]] h6(. » [[Vectors]] h6((. » [[Software Vector Numbers]] h6(((. » UKVDU23V h2. Unknown VDU 23 Vector (23) |_<^{width:3em}. Entry |<^. | |<^. R0|<^. VDU 23 option| |<^. R1|<^. Pointer to VDU 23 queue| |_<^{width:3em}. Exit |<^. | |<^. R0|<^. Preserved| |<^. R1|<^. Preserved| h4. Use This vector is called when a [[VDU 23]] command is issued with an unknown parameter. h4. Notes Whenever an unrecognised byte (18-25,28-31) is found following 23 in the VDU stream this vector is called. R0 contains this unknown byte - it is also the first of the 9 bytes in the VDU queue, pointed at by R1. The default owner of this vector does nothing - unknown VDU 23 options are ignored. h4. See also * [[Software Vector Numbers]] * [[VDU 23]]