bool mongoc_topology_description_has_readable_server ( mongoc_topology_description_t *td, const mongoc_read_prefs_t *prefs);
Determines if the topology has a readable server available. Servers are filtered by the given read preferences only if the driver is connected to a replica set, otherwise the read preferences are ignored. This function uses the driver's current knowledge of the state of the MongoDB server or servers it is connected to; it does no I/O and it does not block.
Use this function in a topology-changed callback registered with mongoc_apm_set_topology_changed_cb. For historical reasons, the mongoc_topology_description_t passed to the callback is a const pointer, you must cast away const to pass the pointer to mongoc_topology_description_has_readable_server.
- td: A mongoc_topology_description_t.
- read_prefs: A mongoc_read_prefs_t or NULL for default read preferences.
True if there is a known server matching prefs.
Introduction to Application Performance Monitoring
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