Pointer reading (Scilab gateway)

How to read pointer in a gateway.

Syntax

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,void* pvApiCtx)
{
	SciErr sciErr;

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

	if(nbInputArgument(pvApiCtx) == 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(pvApiCtx) + 1, (void*)pdblData);
	}
	else if(nbInputArgument(pvApiCtx) == 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(pvApiCtx) + 1, 2, 2, pdblData);
	}
	else
	{
		return 0;
	}
	if(sciErr.iErr)
	{
		printError(&sciErr, 0);
		return 0;
	}
	AssignOutputVariable(pvApiCtx, 1) = nbInputArgument(pvApiCtx) + 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

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Last updated:
Wed Jun 15 08:27:54 CEST 2016