Secure String Handling in Windows Applications

/********************************************************************
	InvalidParameter.cpp : Defines the entry point for the console application.
	
	This application uses for demo the _invalid_parameter_handler for check invalid paramter for _s functions

*********************************************************************/

#include "stdafx.h"

#include <stdlib.h> // _invalid_parameter_handler

#define MAX_BUF 10 // Max char for get_s  

#include <tchar.h>
#include <crtdbg.h>
#include <errno.h>
#include<vadefs.h>

/* Custom invalid parameter handler.  This handler is executed instead 

   of the default handler when the CRT encounters invalid parameters*/
void myInvalidParameterHandler(const wchar_t* expression,
							   const wchar_t* function, 
							   const wchar_t* file, 
						       unsigned int line, 
							   uintptr_t pReserved)
{
   wprintf(L"Invalid parameter detected in function %s."
            L" File: %s Line: %d\n", function, file, line);

   wprintf(L"Expression: %s\n", expression);
}


int _tmain(int argc, _TCHAR* argv[])
{
	/* Set the invalid paramter handler, save the old one */
	_invalid_parameter_handler oldHandler, newHandler;
   newHandler = myInvalidParameterHandler;
   oldHandler = _set_invalid_parameter_handler(newHandler);

#if _DEBUG
   wprintf(L"Enter 10 char string includes NULL:");
#endif
	/* Declare variable for get string */
   char safe_getline[MAX_BUF]; 
  

    /* Disable the message box for assertions */
	_CrtSetReportMode( _CRT_ASSERT, 0) ; 
	
	/* Use the following code for display Assert message in window */
	/* Supported mode :  _CRTDBG_MODE_DEBUG, _CRTDBG_MODE_FILE,  _CRTDBG_MODE_WNDW and _CRTDBG_REPORT_MODE */
	//_CrtSetReportMode( _CRT_ASSERT, _CRTDBG_MODE_WNDW); 

	_ASSERTE(gets_s(safe_getline, MAX_BUF));

#if _DEBUG
    wprintf(L"Entered String %S\n", safe_getline);
#endif

	return 0;
}