# General<no value>
The following SimConnect functions are general in nature and essential for using SimConnect. For a list of other functions please see the [SimConnect API Reference](../../simconnect-api-reference/).

 

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| Function                                  | Description                                                                                                                                         |
|-------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------|
| `DispatchProc`                            | Written by the developer of the SimConnect client, as a callback function to handle all the communications with the server                          |
| `SimConnect_Open`                         | Used to send a request to the Flight Simulator server to open up communications with a new client.                                                  |
| `SimConnect_Close`                        | Used to request that the communication with the server is ended.                                                                                    |
| `SimConnect_CallDispatch`                 | Used to process the next SimConnect message received through the specified callback function.                                                       |
| `SimConnect_GetNextDispatch`              | Used to process the next SimConnect message received, without the use of a callback function.                                                       |
| `SimConnect_RequestSystemState`           | Used to request information from a number of Flight Simulator system components.                                                                    |
| `SimConnect_SetNotificationGroupPriority` | Used to set the priority of a notification group.                                                                                                   |
| `SimConnect_ExecuteAction`                | Used to call an XML action with a variable number of parameters. Available actions are listed here: [SimConnect Actions](../simconnect-actions/) |

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### System Events

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| Function                                | Description                                                                               |
|-----------------------------------------|-------------------------------------------------------------------------------------------|
| `SimConnect_SubscribeToSystemEvent`     | Used to request that a specific system event is notified to the client.                   |
| `SimConnect_SetSystemEventState`        | Used to turn requests for event information from the server on and off.                   |
| `SimConnect_UnsubscribeFromSystemEvent` | Used to request that notifications are no longer received for the specified system event. |

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