64‑bit file offset for locking



USupported on UNIX


Like DBLHIGHPOS (see DBLHIGHPOS), the DBLHIGH64POS environment variable specifies the maximum file offset for locking, except that you can specify a 64‑bit position.


Either the maximum file offset or WARN, to warn when the lock attempt is rejected.


DBLHIGH64POS sets the maximum file offset for locking when system option #33 is not set (conventional locking). By convention, Synergy ISAM files use the highest addressable file offset to lock during OPEN processing for enforcement of exclusive file locking. This value is normally set to 0x7FFFFFFFFFFFFFE on 64‑bit machines.

At runtime, a lock attempt is made at the default position. If the lock attempt is rejected at that position, it adjusts down until it succeeds. To be warned of this, set DBLHIGH64POS to “WARN.” If you get a fatal “Record locking problem” error, you can either set system option #33 or use DBLHIGH64POS. We recommend using DBLHIGH64POS so that exclusive file sharing is not disabled.


This environment variable should be set only in extreme circumstances; all users accessing the same data files must also have the same setting, including Synergy/DE xfServer.

Setting location

The environment.

Used by

Runtime, fcompare, fconvert, isutl