S-Function Builder - Integrate C or C++ code to create S-functions - Simulink (original) (raw)

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 (system-function) from specifications you provide. A C MEX S-function is a computer language description of a Simulink® block written in C or C++. S-functions use a special calling syntax called the S-function API that enables you to interact with the Simulink engine. This interaction is very similar to the interaction that takes place between the engine and built-in Simulink blocks. To learn more about C MEX S-functions, see What Is an S-Function?. To learn more about building C MEX S-Functions using the S-function Builder block, see Build S-Functions Automatically Using S-Function Builder. For an example with a step-by-step procedure, see Use a Bus with S-Function Builder to Create 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 anS-Function Builder block, Simulink invokes the generated C MEX S-function to call your C or C++ code in the instances of mdlStart, mdlOutputs,mdlDerivatives, mdlUpdate andmdlTerminate methods. To learn how Simulink engine interacts with S-functions, see Simulink Engine Interaction with C S-Functions.

Examples

Ports

Input

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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.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | Boolean | fixed point | bus

Output

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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.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | Boolean | fixed point | bus

Parameters

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Use the S-Function Builder editor to create user-defined parameters. For more information on creating user-defined parameters from the editor, see Specify Ports and Parameters for the S-Function.

Note

You do not need to set these listed Simulink block parameters for this block using the block dialog. The Simulink block parameters are set using the information from theS-Function Builder editor.

Use this parameter to specify the name of your S-function.

Programmatic Use

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

Specify the additional S-function parameters.

The function parameters can be specified as MATLAB expressions or as variables separated by commas. For example:

A, B, C, D, [eye(2,2);zeros(2,2)]

Although individual parameters can be enclosed in brackets, the list of parameters must not be enclosed in brackets.

Programmatic Use

This parameter applies only if this block represents a C MEX S-function and you intend to use the Simulink Coder™ software to generate code from the model containing the block. If you use it, when you are ready to generate code, you must force the coder to rebuild the top model as explained in Control Regeneration of Top Model Code (Simulink Coder).

For more information on using this parameter, see Specify Additional Source Files for an S-Function (Simulink Coder).

Programmatic Use

Block Characteristics

Tips

After you build the S-function with the S-Function Builder block, theget_param function returns information for these parameters:

• Parameters — Additional S-function parameters
• SFunctionModules — Additional files for code generation if the block represents a C MEX S-function

Extended Capabilities

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

Version History

Introduced before R2006a