Function to return a unique sequence number
SEQNO([<workarea | alias>])
The SEQNO() function returns the next unique sequence number for the current table. Automatic locking is performed during the operation of this function if the specified table is opened shareable. The optional <workarea | alias> will return the next unique sequence number from the specified table. If there is no active table the SEQNO() function will return 0.
The SEQNO() function guarantees a unique sequence number even in a multi-user environment. The sequence number will continue increasing even after a PACK operation. A ZAP operation will reset the sequence number to 0. The sequence number of a table can be reset with the command SET SEQNO TO <expN>.
append blank replace custno with seqno()