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ssSetInputPortDirectFeedThrough - Specify the direct feedthrough status of a block's ports

Syntax

void ssSetInputPortDirectFeedThrough(SimStruct *S, int_T port, 
 int_T dirFeed)

Arguments

S: SimStruct representing an S-Function block.
port: Index of the input port whose direct feedthrough property is being set.
dirFeed: Direct feedthrough status of the block specified by port.

Description

Use in mdlInitializeSizes or mdlSetWorkWidths (after ssSetNumInputPorts) to specify the direct feedthrough (0 or 1) for each input port index. If not specified, the default direct feedthrough is 0. Setting direct feedthrough to 0 for an input port is equivalent to saying that the corresponding input port signal is not used in mdlOutputs or mdlGetTimeOfNextVarHit. If it is used, you might or might not see a delay of one simulation step in the input signal. This might cause the simulation solver to issue an error due to simulation inconsistencies.

Note The ssSetInputPortDirectFeedThrough macro becomes a function when you compile your S-function in debug mode (mex -g).

Languages

C, C++

Example

See the S-function matlabroot/toolbox/simulink/simdemos/simfeatures/src/sfun_dtype_io.c used in sfcndemo_dtype_io.mdl and the S-function matlabroot/toolbox/simulink/simdemos/simfeatures/src/sdotproduct.c used in sfcndemo_sdotproduct.mdl.