I'm having an odd problem with a project using VisualStudio 2005 Prof.

When I execute the program below I get this message:

Debug Assertion Failed
Program: ...
File: dbgheap.c
Line: 1252
Expression: _CrtIsValidHeapPointer(pUserData)

---------- START ----------
#include "stdafx.h"

#include <iostream>
using namespace std;

int main( int argc, char * argv[] )
{
        unsigned long lU_tile_size = 2956;
        // read the tile data (jpeg file) into a buffer
        unsigned char * byP_jpeg_file = (unsigned char *)
malloc( lU_tile_size );
        if( byP_jpeg_file == NULL )
        {
                wcout << L"eek - allocating memory failed";
                return 1;
        }

        // PROBLEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEM
        realloc( byP_jpeg_file , 0 );

        return 0;

VS2005 settings:
win32 command line executable
ATL is linked statically
Multithreaded-Debug (/MTd)
runtime checking: both
optimisation is turned off (/Od)

Please help!

this
------------------------------------------------------------------
        int i_error;
        errno = 0;      // reset
        free( byP_jpeg_file );
        if( errno =! 0 )
        {
                wchar_t wct_error[256];
                i_error = _wcserror_s( wct_error , 256 , errno );
                if( i_error != 0 )
                {
                        wcout << L"_wcserror_s() failed";
                        return 3;
                }
                wcout << wct_error;
                return 2;
        }
------------------------------------------------------------------
instead of realloc() makes the program print