# Boolean reading (Scilab gateway)

How to read matrix of boolean.

## Calling Sequence

Input argument profile:

    SciErr getMatrixOfBoolean(void* _pvCtx, int* _piAddress, int* _piRows, int* _piCols, int** _piBool)

Named variable profile:

    SciErr readNamedMatrixOfBoolean(void* _pvCtx, const char* _pstName, int* _piRows, int* _piCols, int* _piBool)

## Arguments

_pvCtx

  Scilab environment pointer, pass in "pvApiCtx" provided by api_scilab.h.

_piAddress

  Address of the Scilab variable.

_pstName

  Name of the variable for "named" functions.

_piRows

  Return number of rows of the variable.

_piCols

  Return number of columns of the variable.

_piBool

  Return address of data array (size: _iRows * _iCols). For "Named" function, _piBool must be allocated before calling function.

SciErr

  Error structure where is stored errors messages history and first error number.

## Description

This help describes how to read matrix of boolean.

## Gateway Source

    #include "api_scilab.h"
    int read_write_boolean(char *fname,unsigned long fname_len)
    {
        SciErr sciErr;
        int i;
        //first variable info : real matrix of double
        int iRows       = 0;
        int iCols       = 0;
        int *piAddr     = NULL;
        int* piBool     = NULL;

        //check input and output arguments
        CheckInputArgument(pvApiCtx, 1,1);
        CheckOutputArgument(pvApiCtx, 1,1);

        //get variable address of the first input argument
        sciErr = getVarAddressFromPosition(pvApiCtx, 1, &piAddr);
        if(sciErr.iErr)
        {
            printError(&sciErr, 0);
            return 0;
        }

        //get size and data from Scilab memory
        sciErr = getMatrixOfBoolean(pvApiCtx, piAddr, &iRows, &iCols, &piBool);
        if(sciErr.iErr)
        {
            printError(&sciErr, 0);
            return 0;
        }

        //Do something with data
        for(i = 0 ; i < iRows * iCols ; i++)
        {
            piBool[i] = piBool[i] == 0 ? 1 : 0;
        }

        sciErr = createMatrixOfBoolean(pvApiCtx, nbInputArgument(pvApiCtx) + 1, iRows, iCols, piBool);
        if(sciErr.iErr)
        {
            printError(&sciErr, 0);
            return 0;
        }

        AssignOutputVariable(pvApiCtx, 1) = nbInputArgument(pvApiCtx) + 1;
        return 0;
    }

## Scilab test script

    a = [%t, %f, %t ; %f, %t, %f ; %t, %f, %t];
    a_ref = [%f, %t, %f ; %t, %f, %t ; %f, %t, %f];
    b = read_write_boolean(a);

    if or(b <> a_ref) then error("failed"), end