# SimConnect_ExecuteAction<no value>
The **SimConnect\_ExecuteAction** function can be used to call an action from an XML file with a variable number of parameters. You can find a full list of available actions here: [SimConnect Actions](../simconnect-actions/)

 

##### Syntax

``` cpp
HRESULT SimConnect_ExecuteAction(
    HANDLE hSimConnect,
    DWORD cbRequestID,
    const char* szActionID,
    DWORD cbUnitSize
    void* pParamValues
    );
```

 

##### Parameters

{{< table-wrapper >}}

| Parameter      | Description                                                 | Type    |
|----------------|-------------------------------------------------------------|---------|
| `hSimConnect`  | Handle to a SimConnect object.                              | Integer |
| `cbRequestID`  | ID of the request to retrieve it in the callback response.  | Integer |
| `szActionID`   | The name of the action.                                     | Char    |
| `cbUnitSize`   | The size of the `pParamValues` data.                        | Integer |
| `pParamValues` | A `void*` that contains all the values packed as byte data. | Void    |

{{< /table-wrapper >}}


 

##### Return Values

The function returns an **HRESULT**. Possible values include, but are not limited to, those in the following table.

{{< table-wrapper >}}

| Return value | Description             |
|--------------|-------------------------|
| S\_OK        | The function succeeded. |
| E\_FAIL      | The function failed.    |

{{< /table-wrapper >}}


 

Note that it is possible to get the following `SIMCONNECT_EXCEPTION` values when using this function:

-   `SIMCONNECT_EXCEPTION_ACTION_NOT_FOUND` (with offset 2)
-   `SIMCONNECT_EXCEPTION_NOT_AN_ACTION` (with offset 2)
-   `SIMCONNECT_EXCEPTION_INCORRECT_ACTION_PARAMS` (with offset 4)

 

##### Remarks

The example below shows one way of how to construct the `pParamValues` parameter for use with this function:

{{< callout context="note" title="NOTE" icon="outline/bulb" >}}

All strings are of a fixed size (256).

{{< /callout >}}

``` cpp
HANDLE  hSimConnect;
// SetHighlight (Bool) - FocusDuration (Float) - SetCamera (Bool) - InstrumentPartId (String 256) - InstrumentHtmlId (String 256)
int paramValuesSize = sizeof(bool) + sizeof(float) + sizeof(bool) + 256 + 256;
unsigned char* pData = new unsigned char[paramValuesSize];
unsigned char* pDataBegin = pData;
bool setHighlightVal = TRUE;
*pData = setHighlightVal;
pData += sizeof(bool);
float focusDurationVal = 5.0f;
memcpy(pData, &focusDurationVal, sizeof(float));
pData += sizeof(float);
bool setCameraVal = FALSE;
*pData = setCameraVal;
pData += sizeof(bool);
char instrumentPartIdVal[256] = { "FUEL_SWITCH_TRANSFER" };
memcpy(pData, &instrumentPartIdVal, 256);
pData += 256;
char instrumentHtmlVal[256] = { "" };
memcpy(pData, &instrumentHtmlVal, 256);
pData += 256;
pData = pDataBegin;
SimConnect_ExecuteAction(hSimConnect, 0, "FocusInstrumentAction", paramValuesSize, pData);
```

 

Alternatively, you can use a struct to form the `pParamValues` parameter:

{{< callout context="note" title="NOTE" icon="outline/bulb" >}}

The struct must be `#pragma pack (1)` because of struct padding.

{{< /callout >}}

``` cpp
#pragma pack (1)
struct FocusInstrumentParams
{
    bool highlightPart;
    float focusDuration;
    bool setCamera;
    char instrumentPartId[256];
    char instrumentHtml[256];
};
#pragma pack (0)
///
HANDLE  hSimConnect;
FocusInstrumentParams params;
params.highlightPart = TRUE;
params.focusDuration = 5.0f;
params.setCamera = FALSE;
strcpy_s(params.instrumentPartId, "FUEL_SWITCH_TRANSFER");
strcpy_s(params.instrumentHtml, "\0");
SimConnect_ExecuteAction(hSimConnect, 0, "FocusInstrumentAction", sizeof(params), &params);
```