" is zero (indicating the current thread wants to modify the object), this function will
report an error if any other thread currently has a lock (read-only or read-write) on the
" is non-zero (indicating the current thread wants read-only access to the object), this
function will report an error only if another thread currently has a read-write lock on the
If the object is a structure, each component object will have its own lock, which is independent of the
lock on the parent object. A component object and its parent can be locked by different threads.
However, as a convenience function this function allows all component objects to be locked in
addition to the supplied object (see
The current thread must unlock the object using datUnlock before it can be locked for use by another
thread. All objects are initially locked by the current thread when they are created. The type of access
available to the object (
" ) determines the type of the initial lock. For
pre-existing objects, this is determined by the access mode specified when calling hdsOpen. For new
and temporary objects, the initial lock is always a read-write lock.
"is non-zero, then an attempt is made to lock any component objects contained within the supplied object. An error is reported if any components cannot be locked due to them being locked already by a different thread. This operation is recursive - any children of the child components are also locked, etc.
"is non-zero) is locked for read-only access. Otherwise it is locked for read-write access.
An error will be reported if the supplied object is currently locked by another thread. If
non-zero, an error is also reported if any component objects contained within the supplied object are
locked by other threads.
The majority of HDS functions will report an error if the object supplied to the function has not been locked for use by the calling thread. The exceptions are the functions that manage these locks - datLock, datUnlock and datLocked.
Attempting to lock an object that is already locked by the current thread will change the type of lock (read-only or read-write) if the lock types differ, but will otherwise have no effect.