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Scilab Help >> API Scilab > legacy > Low level functions > Pointer writing (Scilab gateway)

Pointer writing (Scilab gateway)

How to write pointer in a gateway.

Create from existing data.

Syntax

Input argument profile:

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

Named variable profile:

SciErr createNamedPointer(void* _pvCtx, const char* _pstName, void const** _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.

Syntax

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

#include "api_scilab.h"
int read_pointer(char *fname,void* pvApiCtx)
{
	SciErr sciErr;

	CheckInputArgument(pvApiCtx, 0, 1);
    CheckOutputArgument(pvApiCtx, 0, 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;
		const 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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with contributors 		Last updated:
Tue Feb 25 08:49:23 CET 2020