关于多线程一些疑问？？

2012-11-13 03:04:17 248 阅读 AI 写同款 · GEO 优化AI 选题数据监测一键分发 ›

基于SSM的足浴管理系统(源码+开题) 研究内容：本研究的内容主要包括以下几个方面：首先，我们需要对现有的足浴管理系统进行深入的研究和分析，了解其优缺点；最后，我们需要对新设计的系统进行评估和优化，以满足用户的需求和提升系统的使用体验。因此，开发一种基于SSM的足浴管理系统，能够有效地解决这些问题，提高足浴服务的质量和效率。研究目的：本研究的主要目的是设计和实现一个功能完善、操作简便、用户体验良好的基于SSM的足浴管理系统。通过对系统的研究和设计，我们希望能够为足浴服务行业提供一个高效、便捷的工具，从而推动足浴服务行业的发展。阅读详情







#include "stdafx.h"

#include <stdio.h>   

#include <process.h>   

#include <windows.h>   



long g_nNum;  

unsigned int __stdcall Fun(void *pPM);  

const int THREAD_NUM = 200;   

CRITICAL_SECTION  g_csThreadCode;  



int main()  

{  

	g_nNum = 0;  

	HANDLE  handle[THREAD_NUM];   

	InitializeCriticalSection(&g_csThreadCode);  





	int i = 0;  

	while (i < THREAD_NUM)   

	{ 

		handle[i] = (HANDLE)_beginthreadex(NULL, 0, Fun, NULL, 0, NULL); 

		i++;

	}  

  

	//Sleep(1000);  （如果注释掉为什么会报错？？？）



	DeleteCriticalSection(&g_csThreadCode);  

	system("pause");

	return 0;  

}  



unsigned int __stdcall Fun(void *pPM)  

{  

	EnterCriticalSection(&g_csThreadCode)；  



	g_nNum++;  

	printf("全局资源值为%d\n", g_nNum); 



	LeaveCriticalSection(&g_csThreadCode); 



	

	return 0;  

}

上面那个 sleep 注释掉，为什么能报错啊，难道要等他处理完还是？

...全文

Linux音频调试实战：ALSA架构与tinymix工具的高级应用技巧本文深入探讨了Linux音频调试的核心技术，重点解析了ALSA架构下音频信号的路由与混合机制。通过介绍轻量级命令行工具tinymix的高级应用技巧，指导开发者如何精准排查无声、音量异常、多路音频共存等复杂问题，并分享编写自动化测试脚本以提升嵌入式及智能设备音频开发效率的实战方法。阅读详情

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赵4老师 2012-11-13

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仅供参考

//循环向a函数每次发送200个字节长度（这个是固定的）的buffer,
//a函数中需要将循环传进来的buffer，组成240字节（也是固定的）的新buffer进行处理，
//在处理的时候每次从新buffer中取两个字节打印
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <windows.h>
#include <process.h>
#include <io.h>
//Log{
#define MAXLOGSIZE 10000000
#define ARRSIZE(x) (sizeof(x)/sizeof(x[0]))
#include <time.h>
#include <sys/timeb.h>
#include <stdarg.h>
char logfilename1[]="MyLog1.log";
char logfilename2[]="MyLog2.log";
char logstr[16000];
char datestr[16];
char timestr[16];
char mss[4];
CRITICAL_SECTION cs_log;
FILE *flog;
void Lock(CRITICAL_SECTION *l) {
    EnterCriticalSection(l);
}
void Unlock(CRITICAL_SECTION *l) {
    LeaveCriticalSection(l);
}
void LogV(const char *pszFmt,va_list argp) {
    struct tm *now;
    struct timeb tb;

    if (NULL==pszFmt||0==pszFmt[0]) return;
    if (-1==_vsnprintf(logstr,ARRSIZE(logstr),pszFmt,argp)) logstr[ARRSIZE(logstr)-1]=0;
    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);
            }
            flog=fopen(logfilename1,"a");
            if (NULL==flog) return;
        }
        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}
#define ASIZE    200
#define BSIZE    240
#define CSIZE      2
char Abuf[ASIZE];
char Cbuf[CSIZE];
CRITICAL_SECTION cs_HEX ;
CRITICAL_SECTION cs_BBB ;
struct FIFO_BUFFER {
    int  head;
    int  tail;
    int  size;
    char data[BSIZE];
} BBB;
int No_Loop=0;
void HexDump(int cn,char *buf,int len) {
    int i,j,k;
    char binstr[80];

    Lock(&cs_HEX);
    for (i=0;i<len;i++) {
        if (0==(i%16)) {
            sprintf(binstr,"%03d %04x -",cn,i);
            sprintf(binstr,"%s %02x",binstr,(unsigned char)buf[i]);
        } else if (15==(i%16)) {
            sprintf(binstr,"%s %02x",binstr,(unsigned char)buf[i]);
            sprintf(binstr,"%s  ",binstr);
            for (j=i-15;j<=i;j++) {
                sprintf(binstr,"%s%c",binstr,('!'<buf[j]&&buf[j]<='~')?buf[j]:'.');
            }
            Log("%s\n",binstr);
        } else {
            sprintf(binstr,"%s %02x",binstr,(unsigned char)buf[i]);
        }
    }
    if (0!=(i%16)) {
        k=16-(i%16);
        for (j=0;j<k;j++) {
            sprintf(binstr,"%s   ",binstr);
        }
        sprintf(binstr,"%s  ",binstr);
        k=16-k;
        for (j=i-k;j<i;j++) {
            sprintf(binstr,"%s%c",binstr,('!'<buf[j]&&buf[j]<='~')?buf[j]:'.');
        }
        Log("%s\n",binstr);
    }
    Unlock(&cs_HEX);
}
int GetFromRBuf(int cn,CRITICAL_SECTION *cs,FIFO_BUFFER *fbuf,char *buf,int len) {
    int lent,len1,len2;

    lent=0;
    Lock(cs);
    if (fbuf->size>=len) {
        lent=len;
        if (fbuf->head+lent>BSIZE) {
            len1=BSIZE-fbuf->head;
            memcpy(buf     ,fbuf->data+fbuf->head,len1);
            len2=lent-len1;
            memcpy(buf+len1,fbuf->data           ,len2);
            fbuf->head=len2;
        } else {
            memcpy(buf     ,fbuf->data+fbuf->head,lent);
            fbuf->head+=lent;
        }
        fbuf->size-=lent;
    }
    Unlock(cs);
    return lent;
}
void thdB(void *pcn) {
    char        *recv_buf;
    int          recv_nbytes;
    int          cn;
    int          wc;
    int          pb;

    cn=(int)pcn;
    Log("%03d thdB              thread begin...\n",cn);
    while (1) {
        Sleep(10);
        recv_buf=(char *)Cbuf;
        recv_nbytes=CSIZE;
        wc=0;
        while (1) {
            pb=GetFromRBuf(cn,&cs_BBB,&BBB,recv_buf,recv_nbytes);
            if (pb) {
                Log("%03d recv %d bytes\n",cn,pb);
                HexDump(cn,recv_buf,pb);
                Sleep(1);
            } else {
                Sleep(1000);
            }
            if (No_Loop) break;//
            wc++;
            if (wc>3600) Log("%03d %d==wc>3600!\n",cn,wc);
        }
        if (No_Loop) break;//
    }
}
int PutToRBuf(int cn,CRITICAL_SECTION *cs,FIFO_BUFFER *fbuf,char *buf,int len) {
    int lent,len1,len2;

    Lock(cs);
    lent=len;
    if (fbuf->size+lent>BSIZE) {
        lent=BSIZE-fbuf->size;
    }
    if (fbuf->tail+lent>BSIZE) {
        len1=BSIZE-fbuf->tail;
        memcpy(fbuf->data+fbuf->tail,buf     ,len1);
        len2=lent-len1;
        memcpy(fbuf->data           ,buf+len1,len2);
        fbuf->tail=len2;
    } else {
        memcpy(fbuf->data+fbuf->tail,buf     ,lent);
        fbuf->tail+=lent;
    }
    fbuf->size+=lent;
    Unlock(cs);
    return lent;
}
void thdA(void *pcn) {
    char        *send_buf;
    int          send_nbytes;
    int          cn;
    int          wc;
    int           a;
    int          pa;

    cn=(int)pcn;
    Log("%03d thdA              thread begin...\n",cn);
    a=0;
    while (1) {
        Sleep(100);
        memset(Abuf,a,ASIZE);
        a=(a+1)%256;
        if (16==a) {No_Loop=1;break;}//去掉这句可以让程序一直循环直到按Ctrl+C或Ctrl+Break或当前目录下存在文件No_Loop
        send_buf=(char *)Abuf;
        send_nbytes=ASIZE;
        Log("%03d sending %d bytes\n",cn,send_nbytes);
        HexDump(cn,send_buf,send_nbytes);
        wc=0;
        while (1) {
            pa=PutToRBuf(cn,&cs_BBB,&BBB,send_buf,send_nbytes);
            Log("%03d sent %d bytes\n",cn,pa);
            HexDump(cn,send_buf,pa);
            send_buf+=pa;
            send_nbytes-=pa;
            if (send_nbytes<=0) break;//
            Sleep(1000);
            if (No_Loop) break;//
            wc++;
            if (wc>3600) Log("%03d %d==wc>3600!\n",cn,wc);
        }
        if (No_Loop) break;//
    }
}
int main() {
    InitializeCriticalSection(&cs_log );
    Log("Start===========================================================\n");
    InitializeCriticalSection(&cs_HEX );
    InitializeCriticalSection(&cs_BBB );

    BBB.head=0;
    BBB.tail=0;
    BBB.size=0;

    _beginthread((void(__cdecl *)(void *))thdA,0,(void *)1);
    _beginthread((void(__cdecl *)(void *))thdB,0,(void *)2);

    if (!access("No_Loop",0)) {
        remove("No_Loop");
        if (!access("No_Loop",0)) {
            No_Loop=1;
        }
    }
    while (1) {
        Sleep(1000);
        if (No_Loop) break;//
        if (!access("No_Loop",0)) {
            No_Loop=1;
        }
    }
    Sleep(3000);
    DeleteCriticalSection(&cs_BBB );
    DeleteCriticalSection(&cs_HEX );
    Log("End=============================================================\n");
    DeleteCriticalSection(&cs_log );
    return 0;
}

gaochizhen33 2012-11-13

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去掉了那句sleep后，如何主线程先执行的话，DeleteCriticalSection(&g_csThreadCode)这句话优先在新起的线程执行EnterCriticalSection(&g_csThreadCode)之前执行，后边肯定就会报错了。

appleyk 2012-11-13

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主要是你人品太好了，还没等另起的线程开启并执行EnterCriticalSection(&g_csThreadCode)这句，你的主线程已经跑完DeleteCriticalSection(&g_csThreadCode)这句了，


#include "stdafx.h"
#include <process.h>
#include <iostream>
using namespace std;


int g_nTickets = 50;

CRITICAL_SECTION g_cs;//临界区是一种防止多个线程同时执行一个特定代码节的机制

void Thread1(void*)
{

	while(g_nTickets > 0)
	{
		EnterCriticalSection(&g_cs);

		if(g_nTickets >0)
		{
			cout<<"Thread1 sales :"<<g_nTickets<<endl;
			g_nTickets--;
			LeaveCriticalSection(&g_cs);
		}

	}
}

void Thread2(void*)
{

	while(g_nTickets > 0)
	{
		EnterCriticalSection(&g_cs);

		Sleep(5);
		if(g_nTickets >0)
		{
			cout<<"Thread2 sales :"<<g_nTickets<<endl;
			g_nTickets--;
			LeaveCriticalSection(&g_cs);
		}

	}
}


int _tmain(int argc, _TCHAR* argv[])
{

	InitializeCriticalSection(&g_cs);
	_beginthread(Thread1 , 0 , NULL);
	_beginthread(Thread2 , 0 , NULL);

	getchar();
	DeleteCriticalSection(&g_cs);
	return 0;
}

「已注销」 2012-11-13

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DeleteCriticalSection(&g_csThreadCode); 你把临界值都删掉了，EnterCriticalSection(&g_csThreadCode)不报错才怪。注释掉这句就不会错了

armsword 2012-11-13

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推荐本书《windows核心编程》

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