VS Code C++ program does not display any output while debugging [duplicate]

Question

Take a simple C++ file like this:

#include <iostream>
using namespace std;

int main(void)
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    cout << "Hello World";
    return 0;
}

Set breakpoint at return 0. Setup this launch config:

{
    "name": "g++ build and debug active file",
    "type": "cppdbg",
    "request": "launch",
    "program": "${fileDirname}/${fileBasenameNoExtension}",
    "args": [],
    "stopAtEntry": false,
    "cwd": "${workspaceFolder}",
    "environment": [],
    "externalConsole": false,
    "MIMode": "gdb",
    "setupCommands": [
        {
            "description": "Enable pretty-printing for gdb",
            "text": "-enable-pretty-printing",
            "ignoreFailures": true
        }
    ],
    "preLaunchTask": "g++ build active file",
    "miDebuggerPath": "/usr/bin/gdb"
 }

Goto debug tab in left sidebar and click green run button.

Expected situation: I can see Hello World somewhere.
Actual situation: I cannot see Hello World anywhere.

Right side tabs:

Output: empty
Problems: empty
Terminal 1: cppdbg: temp empty
Terminal 2: Task - g++ build active file content
Debug console: content

How to fix this?

Setup: VS Code 1.33.1 (Official Snap build) on Ubuntu 18.04

Probably by adding a newline to the string. The output may be buffered. — Sami Kuhmonen
– Sami Kuhmonen, Commented May 14, 2019 at 5:50
cout << "Hello World\n"; or even better cout << "Hello World" << endl;. endl outputs a newline and flushes the stream. — john
– john, Commented May 14, 2019 at 5:58
Thanks, putting an endl worked (\n didn't), but that is very weird behavior from VSCode. — Gaurang Tandon
– Gaurang Tandon, Commented May 14, 2019 at 6:06
It's not vs codes behaviour, your operating system buffers output before printing to the console, this is entirely normal and fairly universal across all platforms — Alan Birtles
– Alan Birtles, Commented May 14, 2019 at 6:19
@john there seems to be recent contra information to using std::endl, see ACCU Overload 149 - Don't Use std::endl. I don't think it is a showstopper either way, but curios about your comment. — David C. Rankin
– David C. Rankin, Commented May 14, 2019 at 7:01

Gaurang Tandon · Accepted Answer · 2019-06-11 03:25:41Z

4

According to helpful comments above, also I'll quote Alan:

It's not vs codes behaviour, your operating system buffers output before printing to the console, this is entirely normal and fairly universal across all platforms

Thus I needed to add an extra std::endl to my std::cout statement.

answered Jun 11, 2019 at 3:25

community wiki

Gaurang Tandon

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

VS Code C++ program does not display any output while debugging [duplicate]

1 Answer 1

Comments

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Linked

Related