readLineSync does not support reading Chinese characters from the command line,,,

[laterdayi]

readLineSync does not support reading Chinese characters from the command line,,,

[lrhn]

Which operating system are you using, which shell and console, and with which locale/language/code-page settings (if any)?

What do you do, what did you expect to happen, and what actually happened?

The readLineSync should read from the stdin file descriptor. How inputs come from the command line to that depends on a lot of things, and if the encoding used to put bytes into that file is not the same used to read them back, then things won't work.

[maxfrees]

@lrhn

 Flutter (Channel stable, 3.27.2, on Microsoft Windows [版本 10.0.19045.5487], locale zh-CN)
[√] Windows Version (Installed version of Windows is version 10 or higher)
[√] Android toolchain - develop for Android devices (Android SDK version 34.0.0)

i use vscode terminal，language： chinese

import 'dart:io';

void main() {
  stdout.write("Enter your name : ");
  var res = stdin.readLineSync();
  print(res);
}

When I type a Chinese and enter, I want to get res in Chinese, and the result is garbled

How do I get Chinese input ？

Cursor_7EJKbR8kbC.mp4

ref #41562

[maxfrees]

@lrhn This problem has been around for many years

[laterdayi]

Is there any update? This problem has been around for several years @lrhn

[mraleph]

I think the actual breakage is VSCode terminal itself. If you run this code in Windows Terminal app then it works as expected (notice encoding: utf8 which is unfortunately required):

import 'dart:io';

void main() {
  stdout.write("Enter your name : ");
  var res = stdin.readLineSync(encoding: utf8);
  print(res);
}

It however does not work in VSCode integrated terminal.

I have tried the following C++ code in the VSCode terminal:

#include <cstdio>
#include <windows.h>

int main(int argc, char* argv[]) {
    UINT input_cp = GetConsoleCP();
    CPINFOEX info;
    if (!GetCPInfoExA(input_cp, 0, &info)) {
        perror("failed to get console cp info");
    }
    fprintf(stderr, "current cp: %d %s\n", input_cp, info.CodePageName);
    int nbytes = 0;
    char buf[10];
    while ((nbytes = fread(buf, 1, 10, stdin)) > 0) {
        for (int i = 0; i < nbytes; i++) printf("%02x\n", buf[i]);
    }
    return 0;
}

And it also does not really work with any sort of multibyte inputs. So something is broken in VSCode.

[laterdayi]

import 'dart:convert';
import 'dart:io';

void main() {
  stdout.write("Enter your name : ");
  var res = stdin.readLineSync(encoding: utf8);
  print(res);
}

but this won't work

I think the actual breakage is VSCode terminal itself. If you run this code in Windows Terminal app then it works as expected (notice encoding: utf8 which is unfortunately required):

import 'dart:io';

void main() {
stdout.write("Enter your name : ");
var res = stdin.readLineSync(encoding: utf8);
print(res);
}
It however does not work in VSCode integrated terminal.

I have tried the following C++ code in the VSCode terminal:

#include
#include <windows.h>

int main(int argc, char* argv[]) {
UINT input_cp = GetConsoleCP();
CPINFOEX info;
if (!GetCPInfoExA(input_cp, 0, &info)) {
perror("failed to get console cp info");
}
fprintf(stderr, "current cp: %d %s\n", input_cp, info.CodePageName);
int nbytes = 0;
char buf[10];
while ((nbytes = fread(buf, 1, 10, stdin)) > 0) {
for (int i = 0; i < nbytes; i++) printf("%02x\n", buf[i]);
}
return 0;
}
And it also does not really work with any sort of multibyte inputs. So something is broken in VSCode.

[mraleph]

but this won't work

It seems PowerShell terminal is similarly broken. Windows Terminal app is not broken though.

There seems to be something broken at the terminal level because standard C apis are incapable of reading UTF8 here.

[laterdayi]

This should be a problem with dart. I have tried windows powershell cmd dont work, but nodejs has no problem