Added November 2024
The QFLOCK.SYS file, created dynamically along with its sibling JOBTBL.SYS, keeps track of various kinds of inter-job lock queues. While A-Shell applications are free to implement their own locking schemes to manage race conditions, typically using system file locks either directly or as proxies, QFLOCK.SYS provides a convenient mechanism for managing multi-process access to files or any other abstract resource. Note that when a job exits, any entries it may have left in the QFLOCK.SYS are automatically cleared. See the following topics for more details:
System Parameters
| • | QUEUE: specifies location for both QFLOCK.SYS and JOBTBL.SYS |
| • | SBR=MXLOCK: determines whether a job may lock itself out |
| • | SBR=AXLOCK: affects handling of wildcard lock conflicts |
System Commands
| • | QUTL: view/manage QFLOCK.SYS entries |
Subroutines
| • | XLOCK: general purpose lock operations |
| • | FLOCK: file locking based on QFLOCK.SYS |
