param_persistent()

Global parameters whose names start with an underscore (_) can be made persistent.

This function takes a parameter name and an bool flag indicating whether to add or remove the parameter from the persistent storage.

If the parameter name does not start with an underscore or is empty, the function returns `None` (indicating it is not persistent).

param_persistent(name, flag)

• `0` if the operation was successful.
• `None` if the parameter name is invalid or an error occurs.

Mark “_speed” as persistent

param_persistent("_speed", 1);  

Remove “_speed” from persistent storage

param_persistent("_speed", 0);

Attempting to mark a non-underscore parameter as persistent fails

param_persistent("speed", 1);  // returns None (invalid)

param_get
param_set
param_remove
param_persistent