What's mean LHB flush ?

When my customer use clipper find that the program stopped and LHB flush bit in coordinate system status valid.Who know what the LHB flush bit mean?

This bit is 1 if the lookahead buffer is executing segments but not adding any new segments. It is 0 otherwise. The description of the Coordinate System status bits can be found in the “Turbo PMAC Software Reference Manual” the bit 13 description is on page 267 (electronic 285). click the following link for manual on our WEB-site: http://www.deltatau.com/manuals/pdfs/TURBO%20SRM.pdf?id=634151295542802376 Since the program has stopped this may be due to a run-time error. Check the other status bits in the Coordinate System.