Xmemory Access violation reading location 0xFFFFFFFFFFFFFFFF-CodePudding

Whenever I run this code, I get Exception thrown at 0x00007FF6CA077375 in console test.exe: 0xC0000005: Access violation reading location 0xFFFFFFFFFFFFFFFF. coming from a file named "xmemory", what it is supposed to do is loop through different folders looking for a specified file, so it uses a bit of recursion, I'm not sure if that's part of the problem, it's still a WIP but I need to do something about the Exception first. I am using Visual Studio 17.3.0, C 20 Standard (/std:c 20) and MinGW gcc compiler, in case that helps

#include <string>
#include <vector>
#include <iostream>
#include <filesystem>

using std::filesystem::directory_iterator;
namespace fs = std::filesystem;
using namespace std;

string endstr(string str, string delim) {
    int i = str.length();
    while (str[i] != delim[0])
    {
        if (i == 0) break;
        i--;
    }
    return str.substr(i   1, str.length());
}

string start = "C:\\";
vector<string> explored;
string fl;
string *dir;
string getFile(const char* item, string startPath)
{

    for (const auto& file : directory_iterator(startPath))
    {
        fl = file.path().string();
        cout << fl << endl;
        if (fl == endstr(item, "\\")) {
            return fl;
        }
        else if (file.is_directory()) {
            if (find(explored.begin(), explored.end(), fl) != explored.end()) {
                getFile(item, fl);
            }
        }
        else {
            break;
        }
    }
    explored.push_back(fl);
}

int main() {
    getFile("Terraria.exe", "C:\\");
}

Edit: debeg logs n stuff

Debug

'console test.exe' (Win32): Loaded 'C:\Users\willk\source\repos\console test\x64\Debug\console test.exe'. Symbols loaded.
'console test.exe' (Win32): Loaded 'C:\Windows\System32\ntdll.dll'. 
'console test.exe' (Win32): Loaded 'C:\Windows\System32\kernel32.dll'. 
'console test.exe' (Win32): Loaded 'C:\Program Files\Avast Software\Avast\aswhook.dll'. 
'console test.exe' (Win32): Loaded 'C:\Windows\System32\KernelBase.dll'. 
'console test.exe' (Win32): Loaded 'C:\Windows\System32\msvcp140d.dll'. 
'console test.exe' (Win32): Loaded 'C:\Windows\System32\vcruntime140d.dll'. 
'console test.exe' (Win32): Loaded 'C:\Windows\System32\vcruntime140_1d.dll'. 
'console test.exe' (Win32): Loaded 'C:\Windows\System32\ucrtbased.dll'. 
The thread 0x5cec has exited with code 0 (0x0).
Exception thrown at 0x00007FF703A47415 in console test.exe: 0xC0000005: Access violation reading location 0xFFFFFFFFFFFFFFFF.

Build

Build started...
1>------ Build started: Project: console test, Configuration: Debug x64 ------
1>console test.cpp
1>C:\Users\willk\source\repos\console test\console test\console test.cpp(14,25): warning C4267: 'initializing': conversion from 'size_t' to 'int', possible loss of data
1>C:\Users\willk\source\repos\console test\console test\console test.cpp(45): warning C4715: 'getFile': not all control paths return a value
1>console test.vcxproj -> C:\Users\willk\source\repos\console test\x64\Debug\console test.exe
1>Done building project "console test.vcxproj".
========== Build: 1 succeeded, 0 failed, 0 up-to-date, 0 skipped ==========

CodePudding user response：

What goes wrong here is that getFile returns a bad string (uninitialized/garbage due to not returning any string) after it reaches explored.push_back(fl);. Then back in main, that string is destroyed, but that fails, so you're seeing an access violation coming out of the deep parts of the implementation of the destructor of basic_string.

In general, not returning something from a function that is supposed to return something, is a recipe for Bad Things happening.

While "debug output" rarely contains anything useful (unless you've put it there yourself), stack trace is generally useful because it helps you pin-point what the program was doing when it died: