The code that you generate from a model or component (referenced model or subsystem) is
multi-instance code if it allows your application to maintain
multiple independent instances of the component during execution. For example, you can
generate reentrant, multi-instance code from an entire model by setting the model
configuration parameter Code interface packaging to Reusable
function. For general information about multi-instance models and components,
see Code Reuse.
Under some circumstances, applying storage classes can:
Prevent you from generating multi-instance code.
Cause some data elements to appear in the generated code as singletons, which means that each instance of the model or component directly accesses the same shared, global data, creating dependencies between the instances.
To avoid errors and unexpected generation of single-instance code and singleton data, observe the guidelines and limitations below.
When you apply a storage class directly to a data element (see Apply Storage Classes to Individual Signal, State, and Parameter Data Elements):
To generate multi-instance code, you must apply the storage class only to parameter objects, global data stores, shared local data stores, and root-level I/O.
The storage class yields only singleton data.
When you apply a default storage class by using the Code Mapping Editor (see Configure Default Code Generation for Data (Embedded Coder)—requires Embedded Coder®):
For these data categories, you can generate only singleton data:
Model parameters
External parameter objects
Global data stores
Shared local data stores
For Internal data, you can generate only instance-specific
data, which means each instance of the model or component operates on a separate copy
of the data. For this category, you must use the example storage class
SignalStruct, which appears after preparing a model for code
generation with the Quick Start tool. Alternatively, you can create and use your own
structured storage class by using an Embedded Coder Dictionary.