Inside Macintosh: OpenDoc Class Reference /

Part 1 - Classes and Methods / ODLink

Lock

The Lock method locks this link object, ensuring exclusive read-only access to its content storage unit.

ODBoolean Lock (in ODULong wait, 
                out ODLinkKey key);

wait

The interval to wait for access to be granted.

key

If access is granted, a valid link key; otherwise an undefined, invalid key.

return value

kODTrue if access is granted, otherwise kODFalse.

DISCUSSION

To ensure thread-safe access, you must call this method to acquire a valid link key before you can read the link data. This method grants read-only access; a destination part cannot modify a link's content.

The wait parameter specifies the time you are willing to wait for access to be granted. A value of 0 means no wait and is the only value accepted on the Mac OS platform. If the wait argument is nonzero and the lock cannot be granted, the Lock method returns kODFalse immediately. Other platforms may accept other values with platform-dependent meanings.

A link may be locked by only one object at a time; nested calls to the Lock method deny access.

While your part has the link locked, you must pass the key returned in the key output parameter to all methods that access the link. When you are finished using the link, you must pass this key to the Unlock method to unlock the link.

EXCEPTIONS

kODErrBrokenLink

Internal error; the link-source object disconnected from its destinations.

SEE ALSO

The ODLinkKey type (page 924).
The ODLink::GetContentStorageUnit method (page 352).
The ODLink::Unlock method (page 360).
"Manipulating Links" on page 380 in OpenDoc Programmer's Guide.
"Updating a Link at the Destination" on page 384 in OpenDoc Programmer's Guide.