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Function-Call Split

Provide junction for splitting function-call line

  • Function-Call Split block

Simulink / Ports & Subsystems


The Function-Call Split block allows a function-call line to branch and connect to several function-call subsystems or function-call models.

The function-call subsystem or function-call model connected to the output port of the Function-Call Split block that is marked with a dot executes before the subsystems or models connected to other output ports. If data dependencies between subsystems or models do not support the specified execution order, the Function-Call Split block returns an error. To eliminate this error, consider selecting the Latch input for feedback signals of function-call subsystem outputs parameter on one or more Inport blocks of the function-call subsystems or models involved in a data-dependency loop. Selecting this option delays the corresponding function-call, thereby eliminating the data-dependency loop.

To display the execution order of function-call subsystems connected to branches of a given function-call signal, in the Simulink Editor, on the Debug tab, select Information Overlays and click Execution Order. A pane opens on the Simulink canvas that represents the Execution Order Block List. In the list, the execution order of the function-call subsystems is represented in the form [n]←[m] subsystem block name, where:

  • n indicates the execution order of the subsystem.

  • m indicates the execution order of the block that generates the function-call signal.

  • subsystem block name indicates the name of the function-call subsystem.

The Function-Call Split block supports Signal Label Propagation.

The following model shows how to apply the Latch input for feedback signals of function-call subsystem outputs parameter to work around a data-dependency error caused by a Function-Call Split block. By turning this parameter on in the f1 subsystem's Inport block, the Function-Call Split block ignores the data dependency of signal b. The block breaks the loop of data dependencies between subsystems f1 and g1. The model achieves the behavior of consistently calling f1 to execute before g1. For a given execution step, subsystem f1 uses the g1 output computed at the previous execution step.


The Function-Call Split block has these limitations:

  • All function-call subsystems and models connected to a given function-call signal must reside within the same nonvirtual layer of the model hierarchy.

  • You cannot connect branched function-call subsystems or models and their children directly back to the function-call initiator.

  • Function-call subsystems and models connected to branches of a function-call signal cannot have multiple (muxed) initiators.

  • A Function-Call Split block cannot have its input from a signal with multiple function-call elements.



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A Function-Call Generator block, an S-Function block, a Hit Crossing block, or a Stateflow® chart can provide function-call events.


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Function-call line connected to a function-call subsystem or function-call model.


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Select block icon shape.



Rectangular block icon.


Circular block icon.

Programmatic Use

Block Parameter: IconShape
Type: character vector
Values: 'distinctive' | 'round'
Default: 'distinctive'

Specify the number of function-call signal output ports.



Two function-call output ports.


Integer number

Programmatic Use

Block Parameter: NumOutputPorts
Type: character vector
Values: '2' | '<integer>'
Default: '2'

Select the order of function-call output ports with respect to which port provides a function-call first.



Top port provides function-call first.


Bottom port provides function-call first.

Programmatic Use

Block Parameter: OutputPortLayout
Type: character vector
Values: 'default' | 'reverse'
Default: 'default'

Block Characteristics

Data Types


Direct Feedthrough


Multidimensional Signals


Variable-Size Signals


Zero-Crossing Detection


Extended Capabilities

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

Version History

Introduced in R2010a