Shared Access

If access to the file is shared with other processes, any of these intrinsics should be preceded by FLOCK and FUNLOCK intrinsics. This controls access to the records and reduces contention while a modification procedure is being performed. All pointer positioning, read intrinsics, and writing, updating, and deletion procedures should be bounded by the FLOCK and FUNLOCK intrinsics to guarantee that the proper record is updated or deleted.

	NOTE: File locking keeps the file inaccessible to other users until the file is unlocked. This could be a potential source of performance problems. A different file structure may be more suitable for applications in a shared environment.