C++ Segmentation fault on Hello World, cin and cout

Question

I have been trying to get back into C++ after a break of 2 years. On the first day, things went fine. But when I came back the day after, none of my projects containing cout would compile.

The error is:

Exception has occurred. Segmentation fault

The debug console gives me:

Thread 1 received signal SIGSEGV, Segmentation fault.
0x00007ffd9109f436 in std::basic_ostream<char, std::char_traits<char> >::sentry::sentry (this=this@entry=0x5ffda0, __os=...) at /workspace/srcdir/gcc_build/x86_64-w64-mingw32/libstdc++-v3/include/bits/ostream.tcc:51

This is an example of my code where this happens:

#include <iostream>

using namespace std;

int main()
{
    string abc = "a";
    std::cout << "hi";

    return 0;
}

As mentioned, the error happens on std::cout, std::string works fine. There is no difference if I use the namespace std and then only write cout, or if I don't use the namespace and write the whole thing.

The same issue happens if I try to use cin >> abc;

I am using Visual Studio Code. I don't know if it is related, but I'm not getting a c_cpp_properties.json file in my .vscode folder. I am, however, getting the rest, and I do have the c++ addon.

This is on Windows using g++.

I have tried:

• Rebooting
• Uninstalling and reinstalling g++
• Creating new files in new areas
• Checking my path for problematic files.
• Googling the issue, found nothing that seemed relevant

I hope any of you smarter than me can figure out what's wrong.

EDIT: I found the problem, as assumed it was a libstdc++-6.dll file:

Loaded 'C:\Users\xxxx\AppData\Local\Programs\Julia-1.8.2\bin\libstdc++-6.dll'. Symbols loaded.

So yeah, feel pretty stupid, but problem solved.

Answer 1

The problem was a Julia libstdc++-6.dll file that was being loaded before the mingw64 one. If you have a similar problem, make sure to comb through your PATH variables. The Visual Studio Code debug console also tells you what files are being loaded.

BAD:

Loaded 'C:\Users\xxxx\AppData\Local\Programs\Julia-1.8.2\bin\libstdc++-6.dll'. Symbols loaded.

GOOD:

Loaded 'C:\msys64\mingw64\bin\libstdc++-6.dll'. Symbols loaded.

Answer 2

It's a problem with the VS Code executable.

To slove it for Linux you should run/test it from the terminal.

Linux:  

1. (Optional if not already installed) Install g++ in the terminal using the command:
     Ubuntu/Debian: sudo apt update then sudo apt install g++
     Fedora/Red Hat: sudo yum install g++
     Arch Linux: pacman -Syu then pacman -S gcc
   
2. Go into your folder and then compile the script using: g++ -o myfile myfile.cpp
3. Run it using ./myfile

To slove it for Windows you should run/test it from a MinGW enviorment (easiest fix).

Windows:  

1. Download MSYS2 from here.
2. Run the installer. MSYS2 requires 64 bit Windows 8.1 or newer.
3. Enter the Installation Folder (I recommend leaving it default).
4. When done, uncheck option Run MSY2S now, and then click Finsh (or just close the window).
5. Search the program MSYS2 MINGW64 and open it.
6. Now you are in Linux terminal for MinGW (this is a mini Arch Linux).
7. Open in File Explorer the location where you installed it (default C:\msys64\)
8. Now enter in the home folder (there should be your user's folder) then enter in your user's folder.
9. Here is the root folder of the terminal window (basically your workspace).
10. Now you can make your files/folders and they can be found from the terminal. Also you can open VS Code in this location and develop your apps here.
11. Install g++ using pacman -S gcc
12. After you are done use the command in the terminal g++ -o myfile myfile.cpp
13. And run it with ./myfile

Hope that I helped you!

Edit: didn't see you solved it. I was writing it while you solved the problem.