c++ - 在 _beginthread 中接收到错误数据

Question

我想将 int 变量传递给线程。

我的线程代码:

void record_WAVthread(void* data)
{
    int channelId = *(int*)data;
    cout<< "\n THREAD CREATED " << channelId;

    (...)

    _endthread();
}

我的线程创建代码:

extern HANDLE thread_audio_recording[MAX_INPUTS];
extern void record_WAVthread(void* data);

(...)  

case 's':
    if (!flag_recordingAudio) 
    {   
        //start recording
        audioRecManager.isRecording = flag_recordingAudio = true;
        for (int i = 0; i < 16; i++) 
        {
            thread_audio_recording[i] = (HANDLE)_beginthread(record_WAVthread, 0, &i);
        }
    }
    break;

输出:

 THREAD CREATED 0
 THREAD CREATED 5
 THREAD CREATED 5
 THREAD CREATED 9
 THREAD CREATED 14
 THREAD CREATED 15
 THREAD CREATED 12
 THREAD CREATED 11
 THREAD CREATED 9
 THREAD CREATED 12
 THREAD CREATED 8
 THREAD CREATED 7
 THREAD CREATED 4
 THREAD CREATED 2
 THREAD CREATED 3
 THREAD CREATED 6

我做错了什么？我应该得到 1-16。

Answer 1

您将堆栈变量的地址用作线程函数的参数，这是 Windows 多线程编程中的常见错误。

&i 指向一个临时堆栈变量，该变量无法将其值保留在其范围之外。它可以是 case 之后的任何值。您需要使用堆变量作为线程函数的参数。

但对于您的代码，这里有一个特别简单的解决方案。

case 's':
    if (!flag_recordingAudio) 
    {   
        //start recording
        audioRecManager.isRecording = flag_recordingAudio = true;
        for (int i = 0; i < 16; i++) 
        {
            thread_audio_recording[i] = (HANDLE)_beginthread(record_WAVthread, 0, (void*)i);
        }
    }
    break;

void record_WAVthread(void* data)
{
    int channelId = (int)data;
    cout<< "\n THREAD CREATED " << channelId;

    (...)

    _endthread();
}