ifstream is crashing on x64 bit platform - c++

Question

i am trying to use ifstream to open a txt file and read data from that file with ifstream, while that code works just fine on x86 bit platform, it causing weird application crash when using it on x64 bit platform.
ifstream font;
font.open(filename);
if ( font.fail() )
{
return false;
}
// Used to read 95 ASCII characters in the text file
for ( int i = 0; i < 95; i++ )
{
font.get(temp);
while (temp != ' ')
{
font.get(temp);
}
font.get(temp);
while (temp != ' ')
{
font.get(temp);
}
font >> m_Font[i].left;
font >> m_Font[i].right;
font >> m_Font[i].size;
}
Removing font.fail() check causes the program to be stuck at font.get(temp); which means that font.fail() is causing the crash of the program, if someone knows a solution to this problem or can point to an alternate way of reading the text file in this context please let me know.
The reproducible example can be found below, make sure to set the build configuration to x64 and subsystem to Windows`
#include <Windows.h>
#include <iostream>
#include <fstream>
using namespace std;
struct TestStruct
{
int test;
}; TestStruct* testStruct;
bool Test(char* filename)
{
testStruct = new TestStruct[8];
if (!testStruct)
{
return false;
}
ifstream font;
font.open(filename);
if (font.fail())
{
return false;
}
char temp;
for ( int i = 0; i < 8; i++)
{
font.get(temp);
while (temp != ' ')
{
font.get(temp);
}
font.get(temp);
while (temp != ' ')
{
font.get(temp);
}
font >> testStruct[i].test;
}
font.close();
return true;
}
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, PSTR pScmdline, int iCmdshow)
{
AllocConsole();
freopen("CONOUT$", "w", stdout);
while ( Test((char*)"test.txt") )
{
}
return 0;
}
P.S I am failing to reproduce this issue while executing binary by itself from build folder however it still occurs while launching it with local windows debugger attached.

Answer 1

You have an infinite loop that calls the same function with the same parameter. This function does exactly the same procedure but has a side effect of creating an array of TestStruct.
When everything "goes ok", the function returns true, and is called again. One problem is that you never delete the array you are dynamically creating inside of the function. That means that sooner or later you would run out of memory, and this infinite loop would be broken. But it wouldn't be broken in the way you plan it: the operator new (the one that you are using) would throw an exception (std::bad_alloc) instead of returning nullptr.
That is what I see from your code. The compiler may see the same, and it can optimize the code in many strange ways to achieve the same behavior. Try to correct the issues that cause the UB and memory leaks, and maybe the compiler would change it's mind.

Answer 2

So as some pointed out, casting from one string type to another type, in this case from const char* to char* is causing undefined behavior, at first i fixed it in the reproducible example but couldn't fix it in my main project but after changing all string types to the ones that original function is taking it solved the problem, i.e:
D3DX11CreateShaderResourceViewFromFile is taking LPCTSTR and caused a crash while i was trying to cast LPCTSTR from WCHAR*