当我切换到 Edge 时，Windows 控制台应用程序停止打印 [英] Windows console app stops printing when I switch to Edge

查看：29 发布时间：2021/9/25 19:20:50 c++ winapi unicode wchar-t

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问题描述

我必须编写一个控制台应用程序来记录活动窗口的 PID、文本长度和文本.

它可以工作，除非我切换到 Edge.执行不会停止，但只有 PID 和文本长度会打印到屏幕上.

请帮忙，我不知道还能尝试什么.

#include #include #include int main(){//使用环境的默认语言环境作为字符类型setlocale(LC_CTYPE，")；std::cout <<Hello é World！\n";而 (1){//获取前景窗口HWND hwnd = GetForegroundWindow();如果(！hwnd)继续；//获取窗口进程ID双字 pid = 0;GetWindowThreadProcessId(hwnd, &pid);if (pid) std::cout <<pid"<<pid<<"";//获取窗口文本长度int len = GetWindowTextLength(hwnd);//获取窗口文本WCHAR* text = new WCHAR[len + 1];std::cout <<连"<<GetWindowText(hwnd, text, len + 1) <<"";//如果(！文本)继续；//不跳过！所以文本不为空std::wcout <<文字"<<文本;std::cout <<std::endl;文本 = NULL;睡眠(1000)；}返回0；}

解决方案

如果您是从未来开始阅读本文，我会发现以下内容:

TL;DR:Unicode 字符 8203 无法在控制台代码页中表示，这导致 std::wcout 失败.解决方案是检查 std::wcout.fail() 和如果 true 调用 std::wcout.clear().

以下是我深入了解它的方法.

我开始怀疑它与 std::wcout 有关，因为即使我切换到 Microsoft Edge(并在其中切换标签)，以下代码仍会继续打印:

#include #include #include int main(){//使用环境的默认语言环境作为字符类型setlocale(LC_CTYPE，")；而 (1){//获取前景窗口HWND hwnd = GetForegroundWindow();如果(！hwnd)继续；//获取窗口进程ID双字 pid = 0;GetWindowThreadProcessId(hwnd, &pid);std::cout <<pid"<<pid<<"";//获取窗口文本长度int len = GetWindowTextLength(hwnd);//获取窗口文本WCHAR* text = new WCHAR[len + 1];GetWindowText(hwnd, text, len + 1);std::cout <<文字"<<文本<

地点:

PID 3892 - ConsoleApplication1.exe
PID 3144 - Visual Studio 代码
PID 9812 - Slack
PID 8772 - Microsoft Edge - 在执行期间切换选项卡(相同的 PID)

然而，以下代码将停止打印 text ... 行，但保持打印 pid ... 行，当我切换到 Edge(并切换其中的选项卡):

//...std::wcout <<文字"<<文本<

地点:

PID 424 - ConsoleApplication1.exe
PID 3144、9812 和 8772 与之前相同

此外，如果我将 pid ... 和 text ... 行都切换为 wcout，那么控制台输出将完全挂起我一切换到 Edge，就清楚地表明 wcout 流失败了:

//...std::wcout <<pid"<<pid<<""//用 'wcout' 切换 'cout'//...std::wcout <<文字"<<文本<

地点:

PID 13584 - ConsoleApplication1.exe
PID 3144、9812 和 8772 与之前相同

现在我需要知道是什么导致 wcout 失败.根据上面的控制台输出，wcout 似乎在Microsoft"中的 t 之后立即失败.看不见的错误字符，也许?所以我再次调整代码以打印字符及其代码:

//...//std::wcout <<文字"<<文本<

正如预期的那样，Microsoft 中的 t 之后有一个不可见的字符:

解决方案(到目前为止)如下所示.

//std::wcout <<文字"<<文本<

EDIT:找到了一个新的(更好?)解决方案，它不涉及检查 std::wcout.fail() 和调用 std::wcout.clear():

TL;DR:使用 setlocale(LC_CTYPE, "en_US.UTF8") 或(在我的例子中)setlocale(LC_CTYPE, "pt_BR.UTF8").

我想弄清楚为什么默认环境语言环境 (setlocale(LC_CTYPE, "")) 不起作用，所以我设计了以下小实验:

std::cout <<默认语言环境"<<setlocale(LC_CTYPE，NULL)<

<头>

方法	默认语言环境	默认CP	新语言环境	新CP	`wcout` 失败?
`setlocale(LC_CTYPE, "")`	C	850	Portuguese_Brazil.1252	850	是
`setlocale(LC_CTYPE, "en_US.UTF8")`	C	850	en_US.UTF8	850	没有
`setlocale(LC_CTYPE, "pt_BR.UTF8")`	C	850	pt_BR.UTF8	850	没有
`SetConsoleOutputCP(850)` OEM 多语言拉丁语 1；西欧 (DOS)	C	850	C	850	是
`SetConsoleOutputCP(1252)` ANSI 拉丁语 1;西欧 (Windows)	C	850	C	1252	是
`SetConsoleOutputCP(65001)` Unicode (UTF-8)	C	850	C	65001	是

在我的计算机 (Windows 10 x86-64) 中，常量 CP_WINANSI 和 CP_WINUNICODE 映射到 850 和 CP_UTF8到<代码>65001.

推荐阅读:

https://docs.microsoft.com/en-us/windows/console/console-code-pages

I have to write a console app to log the active window PID, text length and text.


It works except when I switch to Edge. The execution doesn't stop, but only the PID and text length get printed to the screen.
Please help, I don't know what else to try.
#include <iostream>
#include <Windows.h>
#include <WinUser.h>

int main()
{
    // Use environment's default locale for char type
    setlocale(LC_CTYPE, "");
    std::cout << "Hello é World!\n";

    while (1)
    {
        // Get foreground window
        HWND hwnd = GetForegroundWindow();
        if (!hwnd) continue;

        // Get window process ID
        DWORD pid = 0;
        GetWindowThreadProcessId(hwnd, &pid);
        if (pid) std::cout << "pid " << pid << " ";

        // Get window text length
        int len = GetWindowTextLength(hwnd);

        // Get window text
        WCHAR* text = new WCHAR[len + 1];
        std::cout << "len " << GetWindowText(hwnd, text, len + 1) << " ";
        //if (!text) continue; // not skipping! so text NOT null
        std::wcout << "text " << text;

        std::cout << std::endl;

        text = NULL;
        
        Sleep(1000);
    }

    return 0;
}

 解决方案 
If you're reading this from the future, here's what I found out:
TL;DR: Unicode char 8203 wasn't representable in the console codepage, which caused std::wcout to fail. The solution is to check for std::wcout.fail() and if true call std::wcout.clear().
Here's how I got to the bottom of it.
I started suspecting it had something to do with std::wcout because the following code would keep printing even when I switched to Microsoft Edge (and switched tabs within it):
#include <iostream>
#include <Windows.h>
#include <WinUser.h>

int main()
{
    // Use environment's default locale for char type
    setlocale(LC_CTYPE, "");

    while (1)
    {
        // Get foreground window
        HWND hwnd = GetForegroundWindow();
        if (!hwnd) continue;

        // Get window process ID
        DWORD pid = 0;
        GetWindowThreadProcessId(hwnd, &pid);
        std::cout << "pid " << pid << " ";

        // Get window text length
        int len = GetWindowTextLength(hwnd);

        // Get window text
        WCHAR* text = new WCHAR[len + 1];
        GetWindowText(hwnd, text, len + 1);
        std::cout << "text " << text << std::endl;

        text = NULL;
        Sleep(1000);
    }

    return 0;
}

Where:

PID 3892 - ConsoleApplication1.exe
PID 3144 - Visual Studio Code
PID 9812 - Slack
PID 8772 - Microsoft Edge - with tabs switched during execution (same PID)

The following code, however, would stop printing the text ... line but keep printing the pid ... line when I switched to Edge (and switched tabs within it):
// ...
std::wcout << "text " << text << std::endl; // switched 'cout' with 'wcout'
// ...

Where:

PID 424 - ConsoleApplication1.exe
PIDs 3144, 9812 and 8772 same as before

Also, if I switched both pid ... and text ... lines to wcout, then the console output would completely hang as soon as I switched to Edge, clearly showing that the wcout stream had failed:
// ...
std::wcout << "pid " << pid << " "; // switched 'cout' with 'wcout'
// ...
std::wcout << "text " << text << std::endl; // same
// ...

Where:

PID 13584 - ConsoleApplication1.exe
PIDs 3144, 9812 and 8772 same as before

Now I needed to know what was causing wcout to fail. Per the console outputs above, wcout seemed to fail right after the t in "Microsoft". Invisible faulty char, maybe? So I tweaked the code once more to print both the char and its code:
// ...
// std::wcout << "text " << text << std::endl;
for (int i = 0; i < wcslen(text); i++) std::cout << (char)text[i] << " (" << (int)text[i] << ")\n";

As expected, there was an invisible char right after the t in Microsoft: Unicode character 8203. Now, finally knowing what to throw on Google (a.k.a. "wcout fail unicode 8203"), I found this and this pivotal answers.
Specifically, the code from @dev7060's comment was the litmus test I needed (here modified):
std::wcout << "abc " << L'\u200b' << " defg" << std::endl; // L'\u200b' is unicode char 8203
if (std::wcout.fail()) {
    std::cout << "\nConversion didn't succeed\n";
    std::wcout << "This statement has no effect on the console";
    std::wcout.clear();
    std::wcout << "hello world from wcout! \n";
}
std::cout << "hello world from cout! \n";
std::wcout << "hello world from wcout again! \n";

The solution (so far) is the one below.
// std::wcout << "text " << text << std::endl;
std::wcout << "text " << text;
if (std::wcout.fail()) std::wcout.clear();
std::cout << std::endl;
EDIT: found a new (better?) solution that doesn't involve checking std::wcout.fail() and calling std::wcout.clear():
TL;DR: use setlocale(LC_CTYPE, "en_US.UTF8") or (in my case) setlocale(LC_CTYPE, "pt_BR.UTF8").
I wanted to figure out why the default environment locale (setlocale(LC_CTYPE, "")) wasn't working, so I devised the following little experiment:
std::cout << "default locale " << setlocale(LC_CTYPE, NULL) << std::endl;
std::cout << "default console output code page " << GetConsoleOutputCP() << std::endl;

setlocale(LC_CTYPE, "pt_BR.UTF8"); // 'method' column from table below
// SetConsoleOutputCP(850)

std::cout << "new locale " << setlocale(LC_CTYPE, NULL) << std::endl;
std::cout << "new console output code page " << GetConsoleOutputCP() << std::endl;





Method
Default locale
Default CP
New locale
New CP
wcout fail?




setlocale(LC_CTYPE, "")
C
850
Portuguese_Brazil.1252
850
Yes


setlocale(LC_CTYPE, "en_US.UTF8")
C
850
en_US.UTF8
850
No


setlocale(LC_CTYPE, "pt_BR.UTF8")
C
850
pt_BR.UTF8
850
No


SetConsoleOutputCP(850)
OEM Multilingual Latin 1; Western European (DOS)
C
850
C
850
Yes


SetConsoleOutputCP(1252)
ANSI Latin 1; Western European (Windows)
C
850
C
1252
Yes


SetConsoleOutputCP(65001)
Unicode (UTF-8)
C
850
C
65001
Yes



In my computer (Windows 10 x86-64), the constants CP_WINANSI and CP_WINUNICODE map to 850 and CP_UTF8 to 65001.
Recommended reading:

https://docs.microsoft.com/en-us/windows/console/console-code-pages


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Method	Default locale	Default CP	New locale	New CP	`wcout` fail?
`setlocale(LC_CTYPE, "")`	C	850	Portuguese_Brazil.1252	850	Yes
`setlocale(LC_CTYPE, "en_US.UTF8")`	C	850	en_US.UTF8	850	No
`setlocale(LC_CTYPE, "pt_BR.UTF8")`	C	850	pt_BR.UTF8	850	No
`SetConsoleOutputCP(850)` OEM Multilingual Latin 1; Western European (DOS)	C	850	C	850	Yes
`SetConsoleOutputCP(1252)` ANSI Latin 1; Western European (Windows)	C	850	C	1252	Yes
`SetConsoleOutputCP(65001)` Unicode (UTF-8)	C	850	C	65001	Yes


                    
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当我切换到 Edge 时，Windows 控制台应用程序停止打印 [英] Windows console app stops printing when I switch to Edge

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