在循环中使用std::condition_variable的问题

[huajie_gis]

我需要每帧执行处理数据与显示数据两个操作，显示的数据依赖于当前每帧处理数据的结果，需要循环每帧这两个操作。先利用C++11线程库对其进行优化。优化思路是这样的：开两个线程，分别循环执行处理数据与显示数据，先执行一次处理数据，以后每帧显示数据利用上一帧处理数据的结果，在显示数据的同时执行处理数据为下一帧显示所用。代码如下：

class SimluateDraw
{
public:
	int ProcessDataLoopFrameCount;
	int PresentDataLoopFrameCount;
	std::mutex Mutex;

	std::condition_variable CV_ProcessData2ndFrameBegin;
	std::condition_variable CV_PresnetDataFrameBegin;
	std::condition_variable CV_ProcessData3rdAndAfterFrameBegin;

	bool ProcessDataLastFrameFinish;
	bool PresentDataCurrentFrameFinish;
	bool FirstPresentDataFrameStart;

	SimluateDraw():
		ProcessDataLoopFrameCount(0U),
		PresentDataLoopFrameCount(0U),
		ProcessDataLastFrameFinish(false),
		PresentDataCurrentFrameFinish(false),
		FirstPresentDataFrameStart(false){}

	void Run()
	{
		std::thread ProcessDataLoopThread(&SimluateDraw::ProcessDataLoop, this);
		std::thread PresentDataLoopThread(&SimluateDraw::PresentDataLoop, this);
		ProcessDataLoopThread.join();
		PresentDataLoopThread.join();
	}

	void ProcessDataLoop()
	{
		auto CullOneFrame = [this]
		{
			ProcessDataLastFrameFinish = false;
			std::this_thread::sleep_for(std::chrono::milliseconds(100));
			OutputDebugString(std::wstring(L"Complete Process Data Frame: " + std::to_wstring(ProcessDataLoopFrameCount++) + L"\n").c_str());
			ProcessDataLastFrameFinish = true;
		};

		while (true)
		{
			if (ProcessDataLoopFrameCount == 0)
			{
				CullOneFrame();
				CV_PresnetDataFrameBegin.notify_one();
			}
			else if (ProcessDataLoopFrameCount == 1)
			{
				std::unique_lock<std::mutex> Lock(this->Mutex);
				CV_ProcessData2ndFrameBegin.wait(Lock, [this] {return FirstPresentDataFrameStart; });
				CullOneFrame();
				Lock.unlock();
				CV_PresnetDataFrameBegin.notify_one();
			}
			else
			{
				std::unique_lock<std::mutex> Lock(this->Mutex);
				CV_ProcessData3rdAndAfterFrameBegin.wait(Lock, [this] {return PresentDataCurrentFrameFinish; });
				CullOneFrame();
				Lock.unlock();
				CV_PresnetDataFrameBegin.notify_one();
			}
		}
	}

	void PresentDataLoop()
	{
		auto DrawOneFrame = [this]
		{
			PresentDataCurrentFrameFinish = false;
			std::this_thread::sleep_for(std::chrono::milliseconds(100));
			OutputDebugString(std::wstring(L"Complete  Present Data Frame: " + std::to_wstring(PresentDataLoopFrameCount++) + L"\n").c_str());
			PresentDataCurrentFrameFinish = true;
		};

		while (true)
		{
			if (!FirstPresentDataFrameStart)
			{
				FirstPresentDataFrameStart = true;
				CV_ProcessData2ndFrameBegin.notify_one();
			}

			std::unique_lock<std::mutex> Lock(this->Mutex);
			CV_PresnetDataFrameBegin.wait(Lock, [this] {return ProcessDataLastFrameFinish; });

			DrawOneFrame();
			Lock.unlock();
			CV_ProcessData3rdAndAfterFrameBegin.notify_one();
		}
	}
};

SimluateDraw simluateDraw;
simluateDraw.Run();

现在问题是，如何我按debug一步一步调试，结果会如我预期那样，每帧都能执行处理数据与显示数据，并且等待某一步也正确。当不是一步一步调试时，结果确大相径庭，先是执行两次处理数据，然后就一直进行显示数据。这时候打断点到处理数据循环进行调试，发现处理数据的循环一直没有被命中，但断点到显示数据循环后再一步一步调试之后又能按照期望运行了。求助呀，这个问题我自己似乎解决不了了。

[huajie_gis]

老哥，还是一样的，打了log跑起来跟按步调试还是出现之前不同的结果。

[赵4老师]

有时不将“调用函数名字＋各参数值，进入函数后各参数值，中间变量值，退出函数前准备返回的值，返回函数到调用处后函数名字＋各参数值＋返回值”这些信息写日志到文件中是无论如何也发现不了问题在哪里的，包括捕获各种异常、写日志到屏幕、单步或设断点或生成core或dmp文件、……这些方法都不行！ 写日志到文件参考下面：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#ifdef _MSC_VER
    #pragma warning(disable:4996)
    #include <windows.h>
    #include <io.h>
#else
    #include <unistd.h>
    #include <sys/time.h>
    #include <pthread.h>
    #define  CRITICAL_SECTION   pthread_mutex_t
    #define  _vsnprintf         vsnprintf
#endif
//Log{
#define MAXLOGSIZE 20000000
#define MAXLINSIZE 16000
#include <time.h>
#include <sys/timeb.h>
#include <stdarg.h>
char logfilename1[]="MyLog1.log";
char logfilename2[]="MyLog2.log";
static char logstr[MAXLINSIZE+1];
char datestr[16];
char timestr[16];
char mss[4];
CRITICAL_SECTION cs_log;
FILE *flog;
#ifdef _MSC_VER
void Lock(CRITICAL_SECTION *l) {
    EnterCriticalSection(l);
}
void Unlock(CRITICAL_SECTION *l) {
    LeaveCriticalSection(l);
}
#else
void Lock(CRITICAL_SECTION *l) {
    pthread_mutex_lock(l);
}
void Unlock(CRITICAL_SECTION *l) {
    pthread_mutex_unlock(l);
}
#endif
void LogV(const char *pszFmt,va_list argp) {
    struct tm *now;
    struct timeb tb;

    if (NULL==pszFmt||0==pszFmt[0]) return;
    _vsnprintf(logstr,MAXLINSIZE,pszFmt,argp);
    ftime(&tb);
    now=localtime(&tb.time);
    sprintf(datestr,"%04d-%02d-%02d",now->tm_year+1900,now->tm_mon+1,now->tm_mday);
    sprintf(timestr,"%02d:%02d:%02d",now->tm_hour     ,now->tm_min  ,now->tm_sec );
    sprintf(mss,"%03d",tb.millitm);
    printf("%s %s.%s %s",datestr,timestr,mss,logstr);
    flog=fopen(logfilename1,"a");
    if (NULL!=flog) {
        fprintf(flog,"%s %s.%s %s",datestr,timestr,mss,logstr);
        if (ftell(flog)>MAXLOGSIZE) {
            fclose(flog);
            if (rename(logfilename1,logfilename2)) {
                remove(logfilename2);
                rename(logfilename1,logfilename2);
            }
        } else {
            fclose(flog);
        }
    }
}
void Log(const char *pszFmt,...) {
    va_list argp;

    Lock(&cs_log);
    va_start(argp,pszFmt);
    LogV(pszFmt,argp);
    va_end(argp);
    Unlock(&cs_log);
}
//Log}
int main(int argc,char * argv[]) {
    int i;
#ifdef _MSC_VER
    InitializeCriticalSection(&cs_log);
#else
    pthread_mutex_init(&cs_log,NULL);
#endif
    for (i=0;i<10000;i++) {
        Log("This is a Log %04d from FILE:%s LINE:%d\n",i, __FILE__, __LINE__);
    }
#ifdef _MSC_VER
    DeleteCriticalSection(&cs_log);
#else
    pthread_mutex_destroy(&cs_log);
#endif
    return 0;
}
//1-79行添加到你带main的.c或.cpp的那个文件的最前面
//81-86行添加到你的main函数开头
//90-94行添加到你的main函数结束前
//在要写LOG的地方仿照第88行的写法写LOG到文件MyLog1.log中