Here are the data structures with brief descriptions:
  OSyncChange | A change object |
| OSyncChangeUpdate | Struct for the change status callback |
| OSyncCustomFilter | Represents a custom filter that can be used to call hooks |
| OSyncDataDetector | Represent a detector for a given format |
| OSyncEngineUpdate | Struct for the engine status callback |
| OSyncError | Represent an error |
| OSyncFilter | Represents a filter to filter changes |
| OSyncFlag | The functions that can be called on a plugin |
| OSyncFormatConverter | Represent a converter from one format to another |
| OSyncFormatEnv | The environment used for conversions |
| OSyncFormatExtension | An extension to a format |
| OSyncFormatFunctions | The functions for accessing formats on a plugin |
| OSyncGroup | Represent a group of members that should be synchronized |
| OSyncHashTable | Represent a hashtable which can be used to check if changes have been modifed or deleted |
| OSyncMappingUpdate | Struct for the mapping status callback |
| OSyncMember | A member of a group which represent a single device |
| OSyncMemberFunctions | Represents the functions that a member will call to inform the syncengine |
| OSyncMemberUpdate | Struct for the member status callback |
| OSyncMessage | A OSyncMessage |
| OSyncObjFormat | Represent a format for a object type |
| OSyncObjType | Represent a abstract object type (like "contact") |
| OSyncPendingMessage | |
| OSyncPlugin | Represent a synchronzation plugin |
| OSyncPluginCallContext | |
| OSyncPluginFunctions | The functions that can be called on a plugin |
| OSyncPluginInfo | Gives information about a plugin |
| OSyncPluginTimeouts | The timeouts for the asynchronous functions of a plugin |
| OSyncQueue | Represents a Queue which can be used to receive messages |
| OSyncThread | |
| OSyncUserInfo | Represent a user |
 OSyncXMLEncoding |
