Multi threaded environment: GNOME Data Access 5 manual

## Multi threaded environment

Each database provider should be usable in a multi threaded environment, even if they impose some restrictions as to how they can be used in such an environment. The Libgda's framework provides some locking mechanism which is:

- if multi threading cannot be supported at all (for example if the client library internally used by the provider does not support it), then the provider's class implementation should set the class's `limiting_thread` attribute to: the GDA_SERVER_PROVIDER_UNDEFINED_LIMITING_THREAD constant. This constant will be resolved at run time as the thread which creates the 1st connection using that provider.

- if multi threading is supported but any connection (or related object) can only be used by the thread in which it was created, then for each opened connection, the "thread-owner" connection's property must be set to the current thread (and other related objects must be locked in a similar way)

- if no locking is done, then the provider is assumed to support full multi threading access, in this case make sure to set class's `limiting_thread` attribute to the NULL constant.

Note that the default provider's class value for the `limiting_thread` is safely set to the GDA_SERVER_PROVIDER_UNDEFINED_LIMITING_THREAD constant.