Cannot change the default input stream on debug.

This is my configuration for the launch.json file:

{
    "name": "(gdb) Launch",
    "type": "cppdbg",
    "request": "launch",
    "program": "${workspaceFolder}/a.exe",
    "args": ["<", "input.txt"],
    "stopAtEntry": false,
    "cwd": "${workspaceFolder}",
    "environment": [
        {"name": "OUTPUT_PATH", "value": "results.txt"}
    ],
    "externalConsole": false,
    "MIMode": "gdb",
    "miDebuggerPath": "C:/cygwin64/bin/gdb.exe",
    "preLaunchTask": "build",
    "setupCommands": [
        {
            "description": "Enable pretty-printing for gdb",
            "text": "-enable-pretty-printing",
            "ignoreFailures": true
        }
    ]
}

Using this:

"args": ["<", "input.txt"]

I wanted to redirect the default input stream to read from the file "input.txt" but this does not work.

Is there any hack around it or it's just a feature that the extension doesn't yet have?

Start with the launch.json configuration and trace how the cppdbg launch request passes its args to gdb, especially when using Cygwin. Reproduce the configuration with input.txt and compare the extension's handling of arguments with the requested default-input behavior. Done means a documented or implemented way to use input.txt as the debugged program's standard input.