Writing S-Functions

Callback Methods

The Level-2 M-file S-function API specifies a set of callback methods that an M-file S-function must implement and others that it may choose to omit, depending on the requirements of the block that the S-function defines. The methods defined by the Level-2 M-file S-function API generally correspond to that of similarly named methods defined by the C MEX-file S-function API. For information on what each method does, see "How Simulink Works" chapter of the Simulink manual) and S-Function Callback Methods.

The following table lists the Level-2 M-file S-function callback methods and their C MEX-file counterparts.

Level-2 M-File Method	C MEX-File Method
Main function (see Main Method)	mdlInitializeSizes
CheckParameters	mdlCheckParameters
Derivatives	mdlDerivatives
Disable	mdlDisable
Enable	mdlEnable
InitializeCondition	mdlInitializeConditions
Outputs	mdlOutputs
ProcessParameters	mdlProcessParameters
SetInputPortComplexSignal	mdlSetInputPortComplexSignal
SetInputPortDataType	mdlSetInputPortDataType
SetInputPortDimensions	mdlSetInputPortDimensionInfo
SetInputPortSampleTime	mdlSetInputPortSampleTime
SetInputPortSamplingMode	mdlSetInputPortFrameData
SetOutputPortComplexSignal	mdlSetOutputPortComplexSignal
SetOutputPortDataType	mdlSetOutputPortDataType
SetOutputPortDimensions	mdlSetOutputPortDimensionInfo
SetOutputPortSampleTime	mdlSetOutputPortSampleTime
Start	mdlStart
Update	mdlUpdate
WriteRTW	mdlRTW
ZeroCrossings	mdlZeroCrossings

Writing Level-2 M-File S-Functions

Main Method

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