Unable to see elements of std::vector with gcc in VS code

For me this works, but check first if you have 'c:\msys64\mingw64\share\gcc-8.3.0\python' or 'c:\usr\share\gcc-8.3.0\python' folder and adjust the snippet

...
            "setupCommands": [
                {
                    "description": "Enable pretty-printing for gdb",
                    "text": "python import sys;sys.path.insert(0, 'c:\\msys64\\mingw64\\share\\gcc-8.3.0\\python');from libstdcxx.v6.printers import register_libstdcxx_printers;register_libstdcxx_printers(None)",
                    "ignoreFailures": false
                },
                {
                    "description": "Enable pretty-printing for gdb",
                    "text": "-enable-pretty-printing",
                    "ignoreFailures": true
                }
            ],
...

I used the method just like Georgy described above.

*((int(*)[10])array._M_impl._M_start)

Debug console output:
-exec p array
$7 = {<std::_Vector_base<int, std::allocator<int> >> = {_M_impl = {<std::allocator<int>> = {<__gnu_cxx::new_allocator<int>> = {<No data fields>}, <No data fields>}, _M_start = 0x2924cb0, _M_finish = 0x2924cd8, _M_end_of_storage = 0x2924cf0}}, <No data fields>}

-exec p *((int(*)[10])array._M_impl._M_start)
$8 = {41, 18467, 6334, 26500, 19169, 15724, 11478, 29358, 26962, 24464}

I also faced a similar problem using MinGW for Windows.

Problem was resolved for me when I removed MINGW and installed mingw-w64 instead.

For Windows:

If you only see memory address for STL containers when debugging, you probably used x64 Windows.

I found one valid solution, when installing MinGW in x64 Windows, install i686 (win32) version (the bottom of this comment gives its official download link) of MinGW instead of x86_64 version, see below:

win32 version of MinGW download:

i686-win32-dwarf

I just extracted the downloaded file into the folder D:\MinGW, then add the bin path of MinGW D:\MinGW\i686-8.1.0-release-posix-dwarf-rt_v6-rev0\mingw32\bin to the PATH of System Variable of environment.

The related config files are below:

.vscode\tasks.json

{
    "tasks": [
        {
            // "type": "shell",
            "label": "C/C++: g++.exe build active file",
            "command": "g++",
            "args": [
                "-g",
                "${file}",
                "-o",
                "${fileDirname}\\${fileBasenameNoExtension}.exe"
            ],
            "options": {
                "cwd": "${workspaceFolder}"
            },
            "problemMatcher": [
                "$gcc"
            ],
            "group": {
                "kind": "build",
                "isDefault": true
            }
        }
    ],
    "version": "2.0.0"
}

.vscode\launch.json

{
    // Use IntelliSense to learn about possible attributes.
    // Hover to view descriptions of existing attributes.    
    "version": "0.2.0",
    "configurations": [
        {
            "name": "g++.exe - Build and debug active file",
            "type": "cppdbg",
            "request": "launch",
            "program": "${fileDirname}\\${fileBasenameNoExtension}.exe",
            "args": [],
            "stopAtEntry": false,
            "cwd": "${workspaceFolder}",
            "environment": [],
            "externalConsole": false,
            "MIMode": "gdb",
            "miDebuggerPath": "gdb",
            "setupCommands": [
                {   // Display content in STL containers pretty
                    "description": "Enable pretty-printing for gdb",
                    "text": "-enable-pretty-printing",
                    "ignoreFailures": true
                }
            ],
            "preLaunchTask": "C/C++: g++.exe build active file"
        }
    ]
}

.vscode\c_cpp_properties.json

{
    "configurations": [
        {
            "name": "Win32",
            "includePath": [
                "${workspaceFolder}/**"
            ],
            "defines": [
                "_DEBUG",
                "UNICODE",
                "_UNICODE"
            ],
            "windowsSdkVersion": "10.0.19041.0",
            "compilerPath": "g++", // Or complete absolute path "D:/MinGW/i686-8.1.0-release-posix-dwarf-rt_v6-rev0/mingw32/bin/g++.exe"
            "cStandard": "c11",
            "cppStandard": "c++17",
            "intelliSenseMode": "clang-x86"
        }
    ],
    "version": 4
}

Environment of my PC

VSCode Version: 1.53.2 (system setup)
OS Version: Windows 10 x64 (Windows_NT x64 10.0.19041)
MinGW version: i686-8.1.0-release-posix-dwarf-rt_v6-rev0
GDB version: 8.1.0 (Target: i686-w64-mingw32)

Initially posted on https://github.com/microsoft/vscode-cpptools/issues/3921#issuecomment-780379258.

May it be helpful for you.

What worked for me in a remote linux machine.

Please check the path '/usr/share/gcc-10/python' on your server. It might be different for you.

"setupCommands": [
    {
        "description": "Enable pretty-printing for gdb",
        "text": "python import sys; sys.path.append('/usr/share/gcc-10/python');sys.path.insert(0, '/usr/bin/python');from libstdcxx.v6.printers import register_libstdcxx_printers;register_libstdcxx_printers(None)",
        "ignoreFailures": false
    },
    {
        "description": "Enable pretty-printing for gdb",
        "text": "-enable-pretty-printing",
        "ignoreFailures": true
    }
]

This problem may be due to a python issue with gdb. I recommend to use msys2 + mingw. It work fine and you get last version of gcc. How to install mingw with msys2:

• install msys2
• pacman -Suy
• pacman -S mingw-w64-x86_64-gcc
• pacman -S mingw-w64-x86_64-gdb
• pacman -S mingw-w64-x86_64-make
• add 'D:\msys64\mingw64\bin' to path ENV