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Passing Two or More Inputs or Outputs

The plhs and prhs parameters are vectors that contain pointers to each left-hand side (output) variable and right-hand side (input) variable. Accordingly, plhs(1) contains a pointer to the first left-hand side argument, plhs(2) contains a pointer to the second left-hand side argument, and so on. Likewise, prhs(1) contains a pointer to the first right-hand side argument, prhs(2) points to the second, and so on.

This routine multiplies an input scalar times an input scalar or matrix.

As this example shows, creating MEX-file gateways that handle multiple inputs and outputs is straightforward. All you need to do is keep track of which indices of the vectors prhs and plhs correspond to which input and output arguments of your function. In this example, the input variable x corresponds to prhs(1) and the input variable y to prhs(2).

For an input scalar x and a real 3-by-3 matrix,


yields this result

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