Pointer reading (Scilab gateway)

How to read pointer in a gateway.

Calling Sequence

Input argument profile:

SciErr getPointer(void* _pvCtx, int* _piAddress, void** _pvPtr)

Named variable profile:

SciErr readNamedPointer(void* _pvCtx, const char* _pstName, void** _pvPtr)

Arguments

:_pvCtx Scilab environment pointer, pass in “pvApiCtx” provided by

api_scilab.h

: :_piAddress Address of the Scilab variable. : :_pvPtr Return address of pointer. : :SciErr Error structure where is stored errors messages history and

first error number.

:

Description

This help describes how pointer can be handled through the Scilab API.

Gateway Source

#include "api_scilab.h"
int read_pointer(char *fname,unsigned long fname_len)
{
    SciErr sciErr;

    CheckInputArgument(pvApiCtx, 0, 1);
    CheckOutputArgument(pvApiCtx, 1, 1);

    if(nbInputArgument == 0)
    {//create mode
            double* pdblData    = (double*)malloc(sizeof(double) * 2 * 2);
            pdblData[0]                     = 1;
            pdblData[1]                     = 3;
            pdblData[2]                     = 2;
            pdblData[3]                     = 4;
            sciErr = createPointer(pvApiCtx, nbInputArgument + 1, (void*)pdblData);
    }
    else if(nbInputArgument == 1)
    {//read mode
            int iType                       = 0;
            int* piAddr                     = NULL;
            void* pvPtr                     = NULL;
            double* pdblData        = NULL;
            sciErr = getVarAddressFromPosition(pvApiCtx, 1, &piAddr);
            if(sciErr.iErr)
            {
                    printError(&sciErr, 0);
                    return 0;
            }
            sciErr = getPointer(pvApiCtx, piAddr, &pvPtr);
            if(sciErr.iErr)
            {
                    printError(&sciErr, 0);
                    return 0;
            }
            pdblData = (double*)pvPtr;
            sciErr = createMatrixOfDouble(pvApiCtx, nbInputArgument + 1, 2, 2, pdblData);
    }
    else
    {
            return 0;
    }
    if(sciErr.iErr)
    {
            printError(&sciErr, 0);
            return 0;
    }
    AssignOutputVariable(1) = nbInputArgument + 1;
    return 0;
}

Scilab test script

b_ref = [1,2;3,4];
a = read_pointer();
b = read_pointer(a);
if `or`_(b <> b_ref) then `error`_("failed"), end