Global variables not showing up in "Variables" tab while debugging

[npdhere]

Hi there,

My setup:
Am using C/C++ for Visual Studio Code (version 1.25.3) and OpenOCD (0.12.0) and JLink for debugging and am enabling the debugging using launch configs and setup commands. Attaching my configs here:

        const debugConfig = {
            name: "(gdb) Launch",
            type: "cppdbg",
            request: "launch",
            program: elfFilePath,
            showGlobalVariables: true,
            cwd: "${workspaceFolder}",
            windows: {
                MIMode: "gdb",
                miDebuggerPath
            },
            linux: {
                MIMode: "gdb",
                miDebuggerPath
            },
            targetArchitecture: "arm",
            console: "integratedTerminal",
            hardwareBreakpoints: {
                "require": true,
                "limit": 30
            },
            symbolLoadInfo: {
                "loadAll": true,
                "exceptionList": ""
            },
            stopAtEntry: true,
            setupCommands: [
                { text: "target extended-remote :3333" },
                { text: "file filepath.elf" },
                { text: "monitor reset init"},
                { text: "monitor halt"},
                { text: "load" },
                { text: "set breakpoint auto-hw on" },
                { text: "monitor arm semihosting enable"},
                { text: "-enable-pretty-printing" },
                { text: "set print pretty on" },
                { text: "hbreak main" },
            ],               
            rtos: "FreeRTOS",
            servertype: "jlink",
            logging: {
                engineLogging: false,
                trace: false,
                traceResponse: false,
                programOutput: true
            }
        };

When pausing the debugger, I could see the local variables and registers but could not see global variables. I tried showGlobalVariables: true, doesnt worked. I could track a sepcific variable by adding it to watch, but I need to view all the global variables like we do for locals. Is there any command to enable this?

[tigran-sargsyan-w]

The C/C++ (cpptools) debugger doesn’t populate the Variables view with all globals. showGlobalVariables isn’t a supported cppdbg option, so flipping it won’t change that. You can still inspect globals reliably via Watch and by sending GDB commands from the Debug Console.

What works well

1. Add globals to Watch
   Open the Run and Debug panel → WATCH → + and type the symbol name (with namespaces if needed), e.g. g_counter or ns::g_flag.
   If a value isn’t editable, add the address to watch and edit the dereferenced node:

&g_counter

then expand it and use Set Value on the pointee.

2. Ask GDB to list globals (handy when you don’t know the exact name)
   In Debug Console run:

-exec info variables

This prints every global known to GDB. To narrow it down by prefix:

-exec info variables ^g_

You can also search your ELF offline:

nm -C build/firmware.elf | grep ' B '   # BSS globals
nm -C build/firmware.elf | grep ' D '   # data globals

3. Build with debug-friendly flags
   Optimizations often hide or fold variables.

-g3 -Og

is a good balance for stepping/inspection on embedded targets. Avoid -O2/-O3 during debugging.

4. Confirm you’re talking to GDB
   Your cppdbg config with MIMode: "gdb" is right for OpenOCD/J-Link. You can trim unsupported knobs like showGlobalVariables (keeps the config cleaner):

{
    "type": "cppdbg",
    "request": "launch",
    "name": "(gdb) Launch",
    "program": "${workspaceFolder}/path/to.elf",
    "cwd": "${workspaceFolder}",
    "MIMode": "gdb",
    "miDebuggerPath": "/usr/bin/arm-none-eabi-gdb",
    "targetArchitecture": "arm",
    "setupCommands": [
        { "text": "target extended-remote :3333" },
        { "text": "monitor reset init" },
        { "text": "monitor halt" },
        { "text": "load" },
        { "text": "set breakpoint auto-hw on" },
        { "text": "monitor arm semihosting enable" },
        { "text": "-enable-pretty-printing" },
        { "text": "set print pretty on" },
        { "text": "hbreak main" }
    ],
    "stopAtEntry": true,
    "console": "integratedTerminal"
}

Notes for embedded (OpenOCD/J-Link/FreeRTOS)

• Globals update when the core is paused. Live updates while running usually require non-halting techniques/tools; plain GDB over SWD won’t stream variable changes continuously.
• If a symbol is in an unnamed namespace or compiled with heavy LTO, you might need the mangled name (use nm -C to discover it).
• If you prefer an embedded-centric workflow with RTOS helpers, try the Cortex-Debug extension alongside cppdbg. It plays nicely with J-Link/OpenOCD and adds MCU views; you can still use the GDB tricks above.

TL;DR
There isn’t a cpptools toggle that makes a “Globals” tree appear. Use Watch for the few you care about, and Debug Console → -exec info variables when you need to discover names. Build with -g3 -Og to keep globals visible. If this solved it, please mark as Accepted so others can find it faster. 🙌