home.md

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-title: Classes
+title: Subscribe
+summary: Subscribe class is used to receive continuous parameter updates from motorcortex server. It simplifies creating and removing subscription groups.  
+
+---
+
+# Subscribe
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+[Subscribe](Classes/classmcx__cpp_1_1Subscribe.md) class is used to receive continuous parameter updates from motorcortex server. It simplifies creating and removing subscription groups.  [More...](#detailed-description)
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+## Classes
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+|                | Name           |
+| -------------- | -------------- |
+| class | **[mcx_cpp::Subscription](Classes/classmcx__cpp_1_1Subscription.md)**  |
+| class | **[mcx_cpp::Subscribe](Classes/classmcx__cpp_1_1Subscribe.md)**  |
+
+## Types
+
+|                | Name           |
+| -------------- | -------------- |
+| typedef std::shared_ptr< ParameterList > | **[ParameterListPtr](Modules/group__subscribe.md#typedef-parameterlistptr)**  |
+| typedef std::vector< GetParameter > | **[ParameterList](Modules/group__subscribe.md#typedef-parameterlist)**  |
+
+## Functions
+
+|                | Name           |
+| -------------- | -------------- |
+| std::string | **[alias](Modules/group__subscribe.md#function-alias)**() const  |
+| uint32_t | **[id](Modules/group__subscribe.md#function-id)**() const  |
+| void | **[notify](Modules/group__subscribe.md#function-notify)**(const std::function< void(std::vector< GetParameter >)> & clb)  |
+| std::vector< GetParameter > | **[read](Modules/group__subscribe.md#function-read)**() const  |
+|  | **[Subscription](Modules/group__subscribe.md#function-subscription)**(const [motorcortex_GroupStatusMsg](Classes/struct__motorcortex__GroupStatusMsg.md) & group_status_msg)  |
+|  | **[Subscription](Modules/group__subscribe.md#function-subscription)**(const McxStatus & status)  |
+|  | **[Subscription](Modules/group__subscribe.md#function-subscription)**()  |
+| StatusReply | **[unsubscribe](Modules/group__subscribe.md#function-unsubscribe)**(const Subscription & subscription) const <br>Unsubscribes from the group.  |
+| SubscriptionReply | **[subscribe](Modules/group__subscribe.md#function-subscribe)**(std::vector< std::string > path_list, const std::string & group_alias, size_t frequency_divider) const <br>Create a subscription group for a list of the parameters.  |
+| void | **[close](Modules/group__subscribe.md#function-close)**() <br>Closes connection to the server.  |
+| ConnectionReply | **[connect](Modules/group__subscribe.md#function-connect)**(std::string url, const ConnectionOptions & connection_options) <br>Opens a subscribe connection.  |
+| ConnectionReply | **[connect](Modules/group__subscribe.md#function-connect)**(std::string url) <br>Opens a subscribe connection.  |
+| std::string | **[url](Modules/group__subscribe.md#function-url)**() const <br>Returns connection URL.  |
+|  | **[~Subscribe](Modules/group__subscribe.md#function-~subscribe)**() <br>Destructor.  |
+|  | **[Subscribe](Modules/group__subscribe.md#function-subscribe)**(const Request & request) <br>Creates new [Subscribe](Classes/classmcx__cpp_1_1Subscribe.md).  |
+|  | **[Subscribe](Modules/group__subscribe.md#function-subscribe)**()  |
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+## Detailed Description
+
+[Subscribe](Classes/classmcx__cpp_1_1Subscribe.md) class is used to receive continuous parameter updates from motorcortex server. It simplifies creating and removing subscription groups. 
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+[Subscription](Classes/classmcx__cpp_1_1Subscription.md) class represents a group of parameters. It returns the latest values and a timestamp of the group. [Subscription](Classes/classmcx__cpp_1_1Subscription.md) class could be used as an observer, which notifies on every update or could be used as polling.
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+## Types Documentation
+
+### typedef ParameterListPtr
+
+```cpp
+typedef std::shared_ptr< ParameterList > ParameterListPtr;
+```
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+### typedef ParameterList
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+```cpp
+typedef std::vector< GetParameter > ParameterList;
+```
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+## Functions Documentation
+
+### function alias
+
+```cpp
+std::string alias() const
+```
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+### function id
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+```cpp
+uint32_t id() const
+```
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+### function notify
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+```cpp
+void notify(
+    const std::function< void(std::vector< GetParameter >)> & clb
+)
+```
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+### function read
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+```cpp
+std::vector< GetParameter > read() const
+```
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+### function Subscription
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+```cpp
+explicit Subscription(
+    const motorcortex_GroupStatusMsg & group_status_msg
+)
+```
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+### function Subscription
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+```cpp
+explicit Subscription(
+    const McxStatus & status
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+```
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+### function Subscription
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+```cpp
+Subscription()
+```
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+### function unsubscribe
+
+```cpp
+StatusReply unsubscribe(
+    const Subscription & subscription
+) const
+```
+
+Unsubscribes from the group. 
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+**Return**: a promise, which resolves when the unsubscribe operation is complete, fails otherwise. 
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+### function subscribe
+
+```cpp
+SubscriptionReply subscribe(
+    std::vector< std::string > path_list,
+    const std::string & group_alias,
+    size_t frequency_divider
+) const
+```
+
+Create a subscription group for a list of the parameters. 
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+**Return**: a subscription handle, which acts as a Promise, it is resolved when subscription is ready or failed. After the subscription is ready the handle is used to retrieve latest data. 
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+### function close
+
+```cpp
+void close()
+```
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+Closes connection to the server. 
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+### function connect
+
+```cpp
+ConnectionReply connect(
+    std::string url,
+    const ConnectionOptions & connection_options
+)
+```
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+Opens a subscribe connection. 
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+**Return**: status of the connection. 
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+### function connect
+
+```cpp
+ConnectionReply connect(
+    std::string url
+)
+```
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+Opens a subscribe connection. 
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+**Return**: status of the connection. 
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+### function url
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+```cpp
+std::string url() const
+```
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+Returns connection URL. 
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+### function ~Subscribe
+
+```cpp
+~Subscribe()
+```
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+Destructor. 
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+### function Subscribe
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+```cpp
+explicit Subscribe(
+    const Request & request
+)
+```
+
+Creates new [Subscribe](Classes/classmcx__cpp_1_1Subscribe.md). 
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+### function Subscribe
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+```cpp
+Subscribe()
+```
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----
 
-# Classes
-
-
-
-* **struct [_AllTypes](Classes/struct__AllTypes.md)**
-* **struct [_EmptyMessage](Classes/struct__EmptyMessage.md)**
-* **struct [_Limits](Classes/struct__Limits.md)**
-* **struct [_SubMessage](Classes/struct__SubMessage.md)**
-* **struct [_motorcortex_ConsoleCmdListMsg](Classes/struct__motorcortex__ConsoleCmdListMsg.md)**
-* **struct [_motorcortex_ConsoleCmdMsg](Classes/struct__motorcortex__ConsoleCmdMsg.md)**
-* **struct [_motorcortex_CreateGroupMsg](Classes/struct__motorcortex__CreateGroupMsg.md)**
-* **struct [_motorcortex_Error](Classes/struct__motorcortex__Error.md)**
-* **struct [_motorcortex_ErrorList](Classes/struct__motorcortex__ErrorList.md)**
-* **struct [_motorcortex_GetParameterListMsg](Classes/struct__motorcortex__GetParameterListMsg.md)**
-* **struct [_motorcortex_GetParameterMsg](Classes/struct__motorcortex__GetParameterMsg.md)**
-* **struct [_motorcortex_GetParameterTreeHashMsg](Classes/struct__motorcortex__GetParameterTreeHashMsg.md)**
-* **struct [_motorcortex_GetParameterTreeMsg](Classes/struct__motorcortex__GetParameterTreeMsg.md)**
-* **struct [_motorcortex_GetSessionTokenMsg](Classes/struct__motorcortex__GetSessionTokenMsg.md)**
-* **struct [_motorcortex_GroupMsg](Classes/struct__motorcortex__GroupMsg.md)**
-* **struct [_motorcortex_GroupParameterInfo](Classes/struct__motorcortex__GroupParameterInfo.md)**
-* **struct [_motorcortex_GroupStatusMsg](Classes/struct__motorcortex__GroupStatusMsg.md)**
-* **struct [_motorcortex_Header](Classes/struct__motorcortex__Header.md)**
-* **struct [_motorcortex_LoadMsg](Classes/struct__motorcortex__LoadMsg.md)**
-* **struct [_motorcortex_LoginMsg](Classes/struct__motorcortex__LoginMsg.md)**
-* **struct [_motorcortex_LogoutMsg](Classes/struct__motorcortex__LogoutMsg.md)**
-* **struct [_motorcortex_OverwriteParameterMsg](Classes/struct__motorcortex__OverwriteParameterMsg.md)**
-* **struct [_motorcortex_ParameterInfo](Classes/struct__motorcortex__ParameterInfo.md)**
-* **struct [_motorcortex_ParameterListMsg](Classes/struct__motorcortex__ParameterListMsg.md)**
-* **struct [_motorcortex_ParameterMsg](Classes/struct__motorcortex__ParameterMsg.md)**
-* **struct [_motorcortex_ParameterOffset](Classes/struct__motorcortex__ParameterOffset.md)**
-* **struct [_motorcortex_ParameterTreeHashMsg](Classes/struct__motorcortex__ParameterTreeHashMsg.md)**
-* **struct [_motorcortex_ParameterTreeMsg](Classes/struct__motorcortex__ParameterTreeMsg.md)**
-* **struct [_motorcortex_ReleaseParameterMsg](Classes/struct__motorcortex__ReleaseParameterMsg.md)**
-* **struct [_motorcortex_RemoveGroupMsg](Classes/struct__motorcortex__RemoveGroupMsg.md)**
-* **struct [_motorcortex_RestoreSessionMsg](Classes/struct__motorcortex__RestoreSessionMsg.md)**
-* **struct [_motorcortex_SaveMsg](Classes/struct__motorcortex__SaveMsg.md)**
-* **struct [_motorcortex_SessionTokenMsg](Classes/struct__motorcortex__SessionTokenMsg.md)**
-* **struct [_motorcortex_SetParameterListMsg](Classes/struct__motorcortex__SetParameterListMsg.md)**
-* **struct [_motorcortex_SetParameterMsg](Classes/struct__motorcortex__SetParameterMsg.md)**
-* **struct [_motorcortex_StatusMsg](Classes/struct__motorcortex__StatusMsg.md)**
-* **namespace [mcx_cpp](Namespaces/namespacemcx__cpp.md)**
-    * **struct [ConnectionOptions](Classes/structmcx__cpp_1_1ConnectionOptions.md)**
-    * **class [ConnectionStatus](Classes/classmcx__cpp_1_1ConnectionStatus.md)**
-    * **class [GetParameter](Classes/classmcx__cpp_1_1GetParameter.md)**
-    * **class [McxStatus](Classes/classmcx__cpp_1_1McxStatus.md)**
-    * **class [ParameterTree](Classes/classmcx__cpp_1_1ParameterTree.md)**
-    * **class [ParameterTreeMsg](Classes/classmcx__cpp_1_1ParameterTreeMsg.md)**
-    * **class [Request](Classes/classmcx__cpp_1_1Request.md)**
-    * **class [SetParameter](Classes/classmcx__cpp_1_1SetParameter.md)**
-        * **struct [safe_underlying_type](Classes/structmcx__cpp_1_1SetParameter_1_1safe__underlying__type.md)**
-        * **struct [safe_underlying_type< T, false >](Classes/structmcx__cpp_1_1SetParameter_1_1safe__underlying__type_3_01T_00_01false_01_4.md)**
-    * **class [Status](Classes/classmcx__cpp_1_1Status.md)**
-    * **class [Subscribe](Classes/classmcx__cpp_1_1Subscribe.md)**
-    * **class [Subscription](Classes/classmcx__cpp_1_1Subscription.md)**
-        * **struct [SharedState](Classes/structmcx__cpp_1_1Subscription_1_1SharedState.md)**
-    * **struct [Worker](Classes/structmcx__cpp_1_1Worker.md)**
-    * **class [WorkerHandle](Classes/classmcx__cpp_1_1WorkerHandle.md)**
-    * **class [WorkerPool](Classes/classmcx__cpp_1_1WorkerPool.md)**
-* **struct [measure](Classes/structmeasure.md)**
-* **namespace [motorcortex](Namespaces/namespacemotorcortex.md)**
-* **struct [pb_bytes_array_s](Classes/structpb__bytes__array__s.md)**
-* **struct [pb_callback_s](Classes/structpb__callback__s.md)**
-* **struct [pb_extension_s](Classes/structpb__extension__s.md)**
-* **struct [pb_extension_type_s](Classes/structpb__extension__type__s.md)**
-* **struct [pb_field_iter_s](Classes/structpb__field__iter__s.md)**
-* **struct [pb_field_s](Classes/structpb__field__s.md)**
-* **struct [pb_istream_s](Classes/structpb__istream__s.md)**
-* **struct [pb_ostream_s](Classes/structpb__ostream__s.md)**
-* **namespace [std](Namespaces/namespacestd.md)**
 
 
 
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-Updated on  7 February 2020 at 16:36:20 CET
+Updated on  7 February 2020 at 16:36:19 CET
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