Obtain a multi-threaded lock for these properties. Other threads will wait
while trying to lock these properties until they are unlocked. Properties
must be unlocked before they are destroyed.
The lock is automatically taken when setting individual properties, this
function is only needed when you want to set several properties atomically
or want to guarantee that properties being queried aren't freed in another
thread.
Lock a group of properties.
Obtain a multi-threaded lock for these properties. Other threads will wait while trying to lock these properties until they are unlocked. Properties must be unlocked before they are destroyed.
The lock is automatically taken when setting individual properties, this function is only needed when you want to set several properties atomically or want to guarantee that properties being queried aren't freed in another thread.