I have a VS2013 VC++ project that I want to create a std::ifstream object like below:
#include "stdafx.h"
#include <fstream>
int _tmain(int argc, _TCHAR* argv[])
{
std::ifstream f;
return 0;
}
It works as expcted but if I change the header included order the compiler will issue an error:
#include <fstream>
#include "stdafx.h"
int _tmain(int argc, _TCHAR* argv[])
{
std::ifstream f;
return 0;
}
error C2065: 'ifstream' : undeclared identifier
What's in the stdafx.h file is very simple:
#pragma once
#include "targetver.h"
#include <stdio.h>
#include <tchar.h>
My problem is why the header included order affects the compiler to find std::ifstream? Is there any macro defined in other headers included by stdafx.h affects the result? But when I press F12 on ifstream class and jump to the definition the class is not grayed out which means they are enabled and the compiler can find them right? I have google for a while but still can't figure out why it compiles fail.
