Synchronizing Access to Resources › &LOCK Verb › Alter the Status of a Resource Lock › Alter the Status from SHR to EXCL

Alter the Status from SHR to EXCL

The following conditions must be satisfied before a request to alter a resource lock status from shared to exclusive will be successful:

• No other procedures can have shared ownership of the resource
• If the resource is the primary resource, there must be no other minor resources (with shared or exclusive status) with the same primary name

If any other shared requests for the lock arrive before the status is altered to exclusive, these new shared requests are given precedence over the change to exclusive, and are granted shared ownership of the lock

If the request is successful the procedure owns the lock exclusively.