Function Element

Specify function to provide via exporting function port

Since R2022a

• 

Libraries:
Simulink / Ports & Subsystems

Description

A Function Element block specifies which port-scoped Simulink^® function in a model is made available through an exporting function port. Use Function Element blocks when you want a function defined inside a referenced model to be callable from other models.

For example, the Function Element block labeled SrvPort.f specifies that the Simulink function, f, is accessible through the exporting function port, SrvPort.

Export Simulink Functions Using Function Element Blocks

When you place a Function Element block at the root level of a referenced model, the corresponding Model block displays an exporting function port. An exporting function port is a port on a Model block that provides access to the function inside the referenced model.

For example, the Model block displays an exporting function port labeled SrvPort.

Note

A Function Element block must be placed at the root level of an export-function model. Each Function Element block must correspond to a port-scoped Simulink Function block at the root level, which defines the function associated with the exporting function port.

Connecting this exporting function port to an invoking function port of another Model block enables a function caller in that model to call the function and receive return values. For more information, see the Function Element Call block.

When to Use Function Element Blocks

Use Function Element blocks when:

• You need a model to provide a function that other models can call.

• You want to reuse function definitions across multiple models.

• You have export-function models that require asynchronous function calls across model boundaries.

Examples

Create Port and Related Blocks

When you insert a Function Element block, the block label populates with default values. The label consists of two interactive text fields: the port name and the function element name. To change the name of the port associated with the block, edit the first text field in the label by clicking the text.

To allow multiple functions to be called through a port, create a Function Element block for each function that you want to include. In the block dialog box, click . Alternatively, hold Ctrl while you drag an existing Function Element block to a new location. Upon releasing the pointer, select New Element.

When multiple blocks are associated with the same port and you change the name of the port, the behavior depends on whether the new port name matches an existing port name.

• If a port with the specified name exists, you assign the block and its element to the specified port. (since R2026a)

• If a port with the specified name does not exist, you rename the port. The corresponding blocks update to reflect the new port name.

To create a port, hold Ctrl while you drag an existing Function Element block to a new location. Upon releasing the pointer, select New Port.

Modify Port Characteristics

In the block dialog box:

• Change port and function element names.

• Reorder function elements by dragging an element into the list of elements.

• Remove blocks associated with selected function elements by clicking the Remove blocks of selected function elements button .

Specify Function Element Name

To change the name of the function element associated with the block, edit the second text field in the label by clicking the text.

All function element names associated with the port must be unique. Each function element name should match the function name of one of the Simulink Function blocks to be called through the port.

Specify Service Interface

To associate the port with a service interface authored in System Composer™, specify the port data type.

Double-click a block associated with the port. Then, select the port name in the tree.

To display the data type, click .

Select a Simulink.ServiceBus object from the Data type list or enter the Simulink.ServiceBus object as Bus: ServiceInterfaceName. The Simulink.ServiceBus object name now appears in parentheses next to the port name.

You can associate a Simulink.ServiceBus object only with the port as a whole, not with individual function elements within the port.

Ports

Input

Port_1 — Full or partial output for external port

function

Connect a function to pass to the corresponding external output port of the parent model.

Parameters

To edit the element associated with a Function Element block, in the Simulink Editor, edit the block label.

To edit port attributes, use the Property Inspector. From the Simulink Toolstrip, on the Simulation tab, in the Prepare gallery, select Property Inspector.

Block Label

Port name — Name of exporting function port

server (default) | port name

Specify a port name that is not already in use by another port. The name appears as a port label on the parent Model block. The name also appears next to the block. Multiple blocks can access the same port.

Use the same port name in the Scope to port parameter of the Trigger block inside the port-scoped Simulink Function block to be called through the port.

Programmatic Use

To set the block parameter value programmatically, use the set_param function.

Parameter:	PortName
Values:	'server' (default) | port name in quotes
Data Types:	char | string

Example: set_param("mymodel/Function Element", PortName="serverPort")

Element — Optional function element specification

f1 (default) | element path

To specify the element that the block selects, in the Simulink Editor, edit the second text field of the block label.

Only one block can access each element.

Programmatic Use

To set the block parameter value programmatically, use the set_param function.

Parameter:	Element
Values:	'f1' (default) | element path in quotes
Data Types:	char | string

Example: set_param("mymodel/Function Element", Element="f3")

Port Tab

To toggle whether the tabs are visible, click .

For information about the port name, see Port name.

Port number — Position of port on parent block

1 (default) | real integer

Specify the order in which the port that corresponds to the block appears on the parent Model block.

• If you add a block that creates another port, the port number is the next available number.

• Deleting all blocks associated with a port deletes the port. The software renumbers other ports to be sequential and does not skip any numbers.

• Specifying a port number that exceeds the number of ports creates a port for that number and for any skipped sequential numbers.

Programmatic Use

To set the block parameter value programmatically, use the set_param function.

Parameter:	Port
Values:	'1' (default) | real integer in quotes
Data Types:	char | string

Example: set_param("mymodel/Function Element", Port="5")

Signal Tab

To toggle whether the tabs are visible, click .

When you specify the port data type, a parenthetical appears next to the port name. To display the specified data type in full, click the attribute summary.

Before R2025a: To specify the port data type, pause on the port name in the tree. Then, click . Alternatively, when available, click the attribute summary.

Data type — Port data type

Inherit: auto (default) | Bus: <object name> | ValueType: <object name>

The port data type can be inherited or specified.

• Inherit: auto — Inherited data type.

• Bus: <object name> — Use the name of the Simulink.ServiceBus object preceded by Bus:. For example, specify Bus: myServiceInterface.

• ValueType: <object name> — Use the name of the Simulink.ValueType object preceded by ValueType:. For example, specify ValueType: windVelocity. The data type of the Simulink.ValueType object must be a Simulink.ServiceBus object.

Tips

• To edit a Simulink.ServiceBus or Simulink.ValueType object, click .

• To create a Simulink.ServiceBus or Simulink.ValueType object, use the Architectural Data Editor or Interface Editor (System Composer).

Programmatic Use

To programmatically set the port data type, use the set_param function. Specify the port as the model name, a forward slash, and the port name.

Parameter:	OutDataTypeStr
Values:	"Inherit: auto" (default) | "Bus: <object name>" | "ValueType: <object name>"

Example: set_param("mymodel/client", OutDataTypeStr="Bus: ServiceInterface")

Block Characteristics

Data Types	Boolean | bus | double | enumerated | fixed point | half | integer | single | string
Direct Feedthrough	no
Multidimensional Signals	yes
Variable-Size Signals	yes
Zero-Crossing Detection	no

Tips

• Use the Filter box to specify a search term to use for filtering a long list of function elements. Do not enclose the search term in quotation marks. The filter does a partial string search and supports regular expressions. To use a regular expression character as a literal, include an escape character (\). For example, to use a question mark, type fcn\?1. For more information, see Regular Expressions.

• To change the background color of a Function Element block, click and select a standard color or specify a custom color. Alternatively, use the BackgroundColor block property. For more information, see Programmatically Specify Block Parameters and Properties.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Version History

Introduced in R2022a

R2026a: Change associated port

Editing the port name in a Function Element block label can now assign the block and its element to a different port. Suppose your model has an exporting function port named MyPort. You add a Function Element block, which corresponds with the default port, server. To associate the new block with MyPort instead of server, in the block label, double-click server and enter MyPort.

R2025a: Specify port attributes more easily

You can now specify port attributes more easily.

• To toggle the display of port attributes, click . Port attributes now appear on the Port and Signal tabs. The button replaces the button that appears when you pause on the port name in a previous release.

• To edit the port name, double-click the name of the port. Alternatively, on the Port tab, specify Port name.

• To change block colors, click and select a standard color or specify a custom color.

• To create a Simulink.Bus object using the Type Editor, on the Signal tab, click .

R2024a: Select new options when dragging block to new location

When you press Ctrl and drag a Function Element block to a new location, you receive clearer options:

• New Port — Create a port.

• New Element — When the dragged block represents an element of the port and not the full port, add an element to the port.

In previous releases, you receive two options:

• Create New Port — Create a port.

• Use Existing Port — When the dragged block represents an element of the port and not the full port, add an element to the port. Otherwise, create a port.

R2024a: Adding or copying block creates a port

These actions now consistently create a port:

• Double-click the canvas. Then, start typing Function Element, and select the block from the menu.

• Copy and paste a Function Element block.

In previous releases, these actions create a port or add an element to a port.