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Scilab manual >> API Scilab > Low level functions > Pointer writing (Scilab gateway)

Pointer writing (Scilab gateway)

How to write pointer in a gateway.

Create from existing data.

Calling Sequence

Input argument profile:

SciErr createPointer(void* _pvCtx, int _iVar, void* _pvPtr)

Named variable profile:

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

Arguments

_pvCtx

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

_iVar

Position in the Scilab memory where you want to put the variable

_pstName

Name of the variable for "named" functions.

_pvPtr

Address of pointer.

SciErr

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

Write directly in Scilab memory.

Calling Sequence

SciErr allocPointer(void* _pvCtx, int _iVar, 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.

Two types of functions can be used to write in the memory of Scilab.

Gateway Source

int read_pointer(char *fname,unsigned long fname_len)
{
    SciErr sciErr;
    CheckRhs(0,1);
    CheckLhs(1,1);

    if(Rhs == 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, Rhs + 1, (void*)pdblData);
    }
    else if(Rhs == 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, Rhs + 1, 2, 2, pdblData);
    }
    else
    {
        return 0;
    }

    if(sciErr.iErr)
    {
        printError(&sciErr, 0);
        return 0;
    }

    LhsVar(1) = Rhs + 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
<< Pointer reading (Scilab gateway) Low level functions Polynomial Symbolic Variable (Scilab gateway) >>
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with contributors 		Last updated:
Wed Jan 26 16:23:48 CET 2011