S-Function Builder

Integrate C or C++ code to create S-functions

Libraries:
Simulink / User-Defined Functions

Description

The S-function Builder block integrates new or existing C or C++ code and creates a C MEX S-function from specifications you provide. See Use a Bus with S-Function Builder to Create an S-Function for detailed instructions on using the S-Function Builder block to generate an S-function.

Instances of the S-Function Builder block also serve as wrappers for generated S-functions in Simulink^® models. When simulating a model that contains instances of an S-Function Builder block, Simulink software invokes the generated S-function in order to call your C or C++ code in the instance mdlStart, mdlOutputs, mdlDerivatives, mdlUpdate and mdlTerminate methods. To learn how Simulink engine interacts with S-functions, see Simulink Engine Interaction with C S-Functions.

Note

The S-Function Builder block does not support masking. However, you can mask a Subsystem block that contains an S-Function Builder block. For more information, see Dynamic Masked Subsystem.

Examples

Inverted Pendulum with Animation

Use a Simulink® to model and animate an inverted pendulum system. An inverted pendulum has its center of mass above its pivot point. To stably maintain this position, the system implements control logic to move the pivot point below the center-of mass as the pendulum starts to fall. The inverted pendulum is a classic dynamics problem used to test control strategies.

Open Model

Custom Code and Hand Coded Blocks Using the S-Function API

This library launches examples of different types of Simulink® S-functions. Simulink S-functions allow you to extend Simulink with new hand coded blocks, interface to custom external code, and create live interfaces to other programs. Use this example to access models containing S-functions in the C, C++, M, and Fortran®.

Open Script

Run Quality Checks on S-Functions

Use S-Function analyzer programmatic interfaces to check S-functions for potential problems and improvements.

Open Model

Ports

Input

expand all

Port_1 — S-function input
scalar | vector | matrix

The S-Function Builder block can accept real and complex, 1-D, or 2-D signals and nonvirtual buses. For each of these cases, the signals must have a data type that Simulink supports.

For more information, see Data Types Supported by Simulink in the Simulink documentation.

Output

expand all

Out — S-function output
scalar | vector | matrix

The S-Function Builder can produce real and complex, 1-D, or 2-D signals and nonvirtual buses. For each of these cases, the signals must have a data type that Simulink supports.

For more information, see Data Types Supported by Simulink in the Simulink documentation.

Parameters

See Build S-Functions Automatically Using S-Function Builder for information about configuring the S-Function Builder block using the S-Function Builder editor.

Block Characteristics

Data Types	`Boolean` \| `double` \| `fixed point` \| `integer` \| `single`
Direct Feedthrough	`no`
Multidimensional Signals	`yes`
Variable-Size Signals	`no`
Zero-Crossing Detection	`no`

Extended Capabilities

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

S-functions that call into MATLAB^® are not supported for code generation.

Fixed-Point Conversion
Design and simulate fixed-point systems using Fixed-Point Designer™.

Version History

Introduced before R2006a

S-Function Builder

Description