String reading (Scilab gateway)

#include "api_scilab.h"
int read_string(char *fname,void* pvApiCtx)
{
	SciErr sciErr;
	int i,j;
	int iLen		= 0;
	//variable info
	int iRows		= 0;
	int iCols		= 0;
	int* piAddr		= NULL;
	int* piLen		= NULL;
	char** pstData	= NULL;
	//output variable
	int iRowsOut	= 1;
	int iColsOut	= 1;
	char* pstOut	= NULL;
	//check input and output arguments

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

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

	//first call to retrieve dimensions
	sciErr = getMatrixOfString(pvApiCtx, piAddr, &iRows, &iCols, NULL, NULL);
	if(sciErr.iErr)
	{
		printError(&sciErr, 0);
		return 0;
	}

	piLen = (int*)malloc(sizeof(int) * iRows * iCols);

	//second call to retrieve length of each string
	sciErr = getMatrixOfString(pvApiCtx, piAddr, &iRows, &iCols, piLen, NULL);
	if(sciErr.iErr)
	{
		printError(&sciErr, 0);
		return 0;
	}

	pstData = (char**)malloc(sizeof(char*) * iRows * iCols);
	for(i = 0 ; i < iRows * iCols ; i++)
	{
		pstData[i] = (char*)malloc(sizeof(char) * (piLen[i] + 1));//+ 1 for null termination
	}

	//third call to retrieve data
	sciErr = getMatrixOfString(pvApiCtx, piAddr, &iRows, &iCols, piLen, pstData);
	if(sciErr.iErr)
	{
		printError(&sciErr, 0);
		return 0;
	}

	//computer length of all strings
	for(i = 0 ; i < iRows * iCols ; i++)
	{
		iLen += piLen[i];
	}

	//alloc output variable
	pstOut = (char*)malloc(sizeof(char) * (iLen + iRows * iCols));
	//initialize string to 0x00
	memset(pstOut, 0x00, sizeof(char) * (iLen + iRows * iCols));

	//concat input strings in output string
	for(i = 0 ; i < iRows ; i++)
	{
		for(j = 0 ; j < iCols ; j++)
		{
			int iCurLen = strlen(pstOut);
			if(iCurLen)
			{
				strcat(pstOut, " ");
			}
			strcpy(pstOut + strlen(pstOut), pstData[j * iRows + i]);
		}
	}

	//create new variable
	sciErr = createMatrixOfString(pvApiCtx, nbInputArgument(pvApiCtx) + 1, iRowsOut, iColsOut, &pstOut);
	if(sciErr.iErr)
	{
		printError(&sciErr, 0);
		return 0;
	}

	//free memory
	free(piLen);

	for(i = 0 ; i < iRows * iCols ; i++)
	{
		free(pstData[i]);
	}

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

a_ref = ["may the puffin be with you"];
a = ["may", "the", "puffin"; "be","with","you"];
b = read_string(a);
if a_ref <> b then error("failed"), end