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Set the dimensions of the signals accepted by an input port




C, C++


void mdlSetInputPortDimensionInfo(SimStruct *S, int_T port,
  const DimsInfo_T *dimsInfo)



SimStruct representing an S-Function block.


Index of a port.


Structure that specifies the signal dimensions supported by the port.

See ssSetInputPortDimensionInfo for a description of this structure.


The Simulink® engine calls this method during dimension propagation with candidate dimensions dimsInfo for port. In C MEX S-functions, if the proposed dimensions are acceptable, the method sets the actual port dimensions, using ssSetInputPortDimensionInfo. If they are unacceptable, the method generates an error via ssSetErrorStatus.

This method is only valid for simulation. A C MEX S-function must enclose the method in a #if defined(MATLAB_MEX_FILE) statement.


This method can set the dimensions of any other input or output port whose dimensions derive from the dimensions of port.

By default, the engine calls this method only if it can fully determine the dimensionality of port from the port to which it is connected. For C MEX S-functions, if the engine cannot completely determine the dimensionality from port connectivity, it invokes mdlSetDefaultPortDimensionInfo. If an S-function can fully determine the port dimensionality from partial information, set the option SS_OPTION_ALLOW_PARTIAL_DIMENSIONS_CALL in mdlInitializeSizes, using ssSetOptions. If this option is set, the engine invokes mdlSetInputPortDimensionInfo even if it can only partially determine the dimensionality of the input port from connectivity.

The engine calls this method until all input ports with inherited dimensions have their dimensions specified.


See sfun_matadd.c for an example of how to use this function.

Version History

Introduced before R2006a