The DTREE procedure is interactive. You start the procedure with the PROC DTREE statement and terminate it with the QUIT statement. It is not necessary to have a VARIABLES statement, although if you do include one, it must appear immediately after the PROC DTREE statement. The other statements such as the EVALUATE, MODIFY, MOVE, RECALL, RESET, SAVE, SUMMARY, TREEPLOT, VPC, and VPI, as well as the FOOTNOTE, GOPTIONS, NOTE, SYMBOL, and TITLE statements of SAS/GRAPH Software can be used in any order and as often as needed. One exception is that the RECALL statement has to be preceded by at least one SAVE statement.

When an error is detected during processing a statement other than the PROC DTREE statement and the QUIT statement, the procedure terminates if the option ERRHANDLE=QUIT is specified; otherwise it stops processing the current statement and waits for the next statement. In either case, an error message is written to the SAS log. If an error is detected in the PROC DTREE statement or the QUIT statement, the procedure terminates immediately with an error message.