C / C++ / MFC

#include "stdio.h"
#include <string.h>
#include "stdlib.h"
#define _CRT_SECURE_NO_WARNINGS

int main()
{
    FILE *p = NULL;
    size_t len = 0;
    unsigned int convertedChars = 0;

    int ret;
    
    wchar_t toTranscode[] = L"ناعسالاخخ";
    //wchar_t toTranscode[] = L"hello";
    unsigned int wLent = wcslen((const wchar_t*)toTranscode);
    //------------------------------------------------------
    // a UTF-8 character can have maximum 6 bytes
    //------------------------------------------------------
    int maxCharLen = 6*wLent;
    wchar_t* pWideCharBuf;
    char* pToFill;
    unsigned int i;

    //--------------------------------------------------------------
    // alloc memory for variables.
    //--------------------------------------------------------------
    pWideCharBuf = (wchar_t*)malloc(wLent+1);
    pToFill = (char*)malloc(maxCharLen+1);

    for (i = 0; i < wLent; ++i)
    pWideCharBuf[i] = toTranscode[i];
    pWideCharBuf[wLent] = 0x00;

    memset (pToFill, 0, maxCharLen+1);
  // convert the string

    //ret = wcstombs(pToFill, pWideCharBuf, maxCharLen);

    ret = wcstombs_s(&convertedChars, pToFill, maxCharLen, pWideCharBuf, maxCharLen);
    //ret = wcstombs_s(&convertedChars, pToFill, maxCharLen, pWideCharBuf, _TRUNCATE);
    printf("ret is %d\n", ret);

    printf("the ascii char is  = %s\n", pToFill);
    printf("to test\n");


    p = fopen("hello.txt", "w");
    if (p== NULL) {
       printf("Error in opening a file..");
    }
   len = strlen(pToFill);
   fwrite(pToFill, len, 1, p);
   fclose(p);
   printf("\nWritten Successfuly in the file.\n");

    // pToFill contains the string

    //-------------------------------------------------------
    // clean-up
    //-------------------------------------------------------
    //lete [] pWideCharBuf ;

    // don't forget to
    //delete [] pToFill ;
    return 0;
}

ON_COMMAND(ID_FILE_OPEN, OnFileOpen)

(KERNELBASE.DLL): 0xC0000005: Access Violation.

ON_COMMAND(ID_FILE_OPEN, CWinApp::OnFileOpen)