The optional APPN diagnostic data is presented in a format similar to the format of a control vector. This data is located after the standard APPN diagnostic data. More than one type of variable data can be present. The type of optional data that is contained in the error log depends on the current session setup state at the time the error or time-out occurred. This data begins at offset X'0312' from the start of the error log entry.
Header information exists at the beginning of each variable data element. This provides the length and key value of the data area element (similar to the way that control vectors are structured).