![]() If that key does not exist, create the key(s).Ĭarry on with the rest of your sketch where data can now be stored and retrieved from the namespace. Test for the existence of a key that should exist if the namespace has been initialized. ![]() The nuance is in initializing everything at the start.īefore you can store or retrieve anything using Preferences, both the namespace and the key within that namespace need to exist. When retrieving information a “ get” method referenced to its key is used.Įnsuring that the data types of your “ get’s” and “ put’s” all match, you’re good to go. When storing information, a “ put” method referenced to its key is used. (Technically, you can retrieve a value if the namespace is open in either read-only or read-write mode but it’s good practice to open the namespace in read-only mode if you are only retrieving values.) Preferences workflow, once everything is initialized, is pretty simple. String values can be stored and retrieved either as an Arduino String or as a null terminated char array (C-string).īytes type is used for storing and retrieving an arbitrary number of bytes in a namespace. Preferences directly suports the following data types: Table 1 - Preferences Types ¶ Store and retrieve data within a namespace for supported data types ĭetermine if a key value has been initialized ĭelete all key-value pairs in a namespace ĭetermine data types stored against a key ĭetermine the number of key entries available in the namespace. Library Overview ¶ Library methods are provided to:
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