> For the complete documentation index, see [llms.txt](https://docs.heisenware.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.heisenware.com/developers/vrpc/languages/arduino/api.md).

# API

## Required dependencies

* [ArduinoJSON](https://arduinojson.org/?utm_source=meta\&utm_medium=library.properties) by Benoit Blanchon
* [PubSubClient](https://pubsubclient.knolleary.net/) by Nick O’Leary
* [ArduinoUniqueId](https://github.com/ricaun/ArduinoUniqueID) by Luiz Henrique Cassettari

## Function adaptation macros

Use the macros described below to add remote access to regular functions.

#### 1. Global Functions

```cpp
VRPC_GLOBAL_FUNCTION(<returnType>, <functionName>[, <argTypes>])
```

Example:

```cpp
int foo () {
  // [...]
}

void bar (String& s, bool b) {
  // [...]
}

VRPC_GLOBAL_FUNCTION(int, foo)
VRPC_GLOBAL_FUNCTION(void, bar, String&, bool)
```

## class `VrpcAgent`

The agent allows existing code to be called from remote.

### Summary

| Members                                                                                                                                                                                                                                                                                        | Descriptions                                                       |
| ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------ |
| `public inline` [`VrpcAgent`](https://github.com/heisenware/vrpc-arduino/blob/master/docs/api.md#classVrpcAgent_1ace51d7fc67e6cca3db088b229292ded7)`(int maxBytesPerMessage)`                                                                                                                  | Constructs an agent.                                               |
| <p><code>public template<></code><br><code>inline void</code> <a href="https://github.com/heisenware/vrpc-arduino/blob/master/docs/api.md#classVrpcAgent_1a5bcc3d82db137a8d4dd37f55ce83d53e"><code>begin</code></a><code>(T & netClient,const String & domain,const String & token)</code></p> | Initializes the object using a client class for network transport. |
| `public inline bool` [`connected`](https://github.com/heisenware/vrpc-arduino/blob/master/docs/api.md#classVrpcAgent_1aef4609a41a89bf7602011cca1fff5057)`()`                                                                                                                                   | Reports the current connectivity status.                           |
| `public inline void` [`connect`](https://github.com/heisenware/vrpc-arduino/blob/master/docs/api.md#classVrpcAgent_1afa4e6b81fcb0a990d5747b986adeecdb)`()`                                                                                                                                     | Connect the agent to the broker.                                   |
| `public inline void` [`loop`](https://github.com/heisenware/vrpc-arduino/blob/master/docs/api.md#classVrpcAgent_1a89c5b7c6a84bccc8470b4bb8ff29a4ff)`()`                                                                                                                                        | This function will send and receive VRPC packets.                  |

### Members

#### `public inline` [`VrpcAgent`](https://github.com/heisenware/vrpc-arduino/blob/master/docs/api.md#classVrpcAgent_1ace51d7fc67e6cca3db088b229292ded7)`(int maxBytesPerMessage)`

Constructs an agent.

**Parameter**

* `maxBytesPerMessage` \[optional, default: `1024`] Specifies the maximum size a single MQTT message may have

***

#### `public template<typename T>` `inline void` [`begin`](https://github.com/heisenware/vrpc-arduino/blob/master/docs/api.md#classVrpcAgent_1a5bcc3d82db137a8d4dd37f55ce83d53e)`(T& netClient, const String& domain, const String& token)`

Initializes the object using a client class for network transport.

**Parameter**

* `netClient` A client class following the interface as described [here](https://www.arduino.cc/en/Reference/ClientConstructor)
* `domain` \[optional, default: `"vrpc"`] The domain under which the agent-provided code is reachable
* `token` \[optional, default: `""`] Access token as generated by Heisenware GmbH, or MQTT password if own broker is used
* `broker` \[optional, default: `"vrpc.io"`] Address of the MQTT broker
* `username` \[optional] MQTT username (not needed when using the vrpc.io broker)

***

#### `public inline bool` [`connected`](https://github.com/heisenware/vrpc-arduino/blob/master/docs/api.md#classVrpcAgent_1aef4609a41a89bf7602011cca1fff5057)`()`

Reports the current connectivity status.

**Returns**

true when connected, false otherwise

***

#### `public inline void` [`connect`](https://github.com/heisenware/vrpc-arduino/blob/master/docs/api.md#classVrpcAgent_1afa4e6b81fcb0a990d5747b986adeecdb)`()`

Connect the agent to the broker.

The function will try to connect forever. Inspect the serial monitor to see the connectivity progress.

***

#### `public inline void` [`loop`](https://github.com/heisenware/vrpc-arduino/blob/master/docs/api.md#classVrpcAgent_1a89c5b7c6a84bccc8470b4bb8ff29a4ff)`()`

Send and receive VRPC packets.

{% hint style="info" %}
**NOTE**

This function should be called in every `loop`
{% endhint %}


---

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