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新手~怎么实现随机启动线程

发布时间： 2013-07-08 14:13:00 作者： rapoo

新手求助~如何实现随机启动线程？
我参考网上搜索到的资料写了一个生产者消费者问题的小程序：


#include<iostream.h>
#include<windows.h>
#include<time.h>
#include <stdio.h>

const int size = 5;   //缓冲区大小
const int producer_count = 5;   //生产者线程个数
const int consumer_count = 5;   //消费者线程个数
const int thread_count = producer_count + consumer_count;   //总线程个数

 int in = 0;    //缓冲区的生产者下标
 int out = 0;   //缓冲区的消费者下标
int buffer[size];    //缓冲区
int product_num = 0;//生产流水号
int consume_num = 0;//消费流水号

HANDLE hmutex;
HANDLE hempty;
HANDLE hfull;

void produce();
void consume();

DWORD WINAPI producer(LPVOID lpParamer)
{
while(true)
{
WaitForSingleObject(hempty,INFINITE);
WaitForSingleObject(hmutex,INFINITE);
produce();
Sleep(1000);
ReleaseMutex(hmutex);
ReleaseSemaphore(hfull,1,NULL);

}
return 0;
}

DWORD WINAPI consumer(LPVOID lpParamer)
{
while(true)
{
WaitForSingleObject(hfull,INFINITE);
WaitForSingleObject(hmutex,INFINITE);
consume();
Sleep(1000);
ReleaseMutex(hmutex);
ReleaseSemaphore(hempty,1,NULL);

}
return 0;
}

void main()
{

hmutex = CreateMutex(NULL,false,NULL);
hempty = CreateSemaphore(NULL,size,size,NULL);     //不确定：初值是size还是size-1，最大值同样不确定
hfull = CreateSemaphore(NULL,0,size,NULL);

HANDLE PThreads[producer_count];//生产者线程的句柄
HANDLE CThreads[consumer_count];//消费者线程的句柄

DWORD   producerID[producer_count];   //生产者线程的标识符 
    DWORD   consumerID[consumer_count];   //消费者线程的标识符  

int i = 0;
int j = 0;
for(i=0;i<5;i++)
{
PThreads[i] = CreateThread(NULL,0,producer,NULL,0,&producerID[i]);
}
for(j=0;j<5;j++)
{
CThreads[j] = CreateThread(NULL,0,consumer,NULL,0,&consumerID[j]);
}

bool g_continue = true;
 while(g_continue){ 
                if(getchar())
{   //按回车后终止程序运行 
                        g_continue   =   false;  
 
                } 
        } 
}

void produce()
{
cout<<"生产第"<<product_num<<"号产品"<<endl;
buffer[in] = product_num;
in = (in + 1) % size;
product_num++;
}

void consume()
{
consume_num = buffer[out];
cout<<"消费第"<<consume_num<<"号产品"<<endl;
out = (out + 1) % size;
}

但是生产和消费的都是固定顺序的：
生产
生产
生产
生产
生产
消费
消费
消费
消费
消费
我想要能够改成随机启动生产者或是消费者的线程，比如：
生产
生产
消费
生产
消费
消费
...
是的生产和消费的顺序不是固定的，而是随机的，请问应该如何实现？
非常感谢！ 多线程
[解决办法]
    for(i=0;i<5;i++)
    {
        PThreads[i] = CreateThread(NULL,0,producer,NULL,0,&producerID[i]);
    }
    for(j=0;j<5;j++)
    {
        CThreads[j] = CreateThread(NULL,0,consumer,NULL,0,&consumerID[j]);
    }

你代码里写的就是按顺序的，当然就是按顺序的了
    for(i=0, j=0;i<5 
[解决办法]
 j< 5;)
    {
        if (i>=5)
        {
            CThreads[j] = CreateThread(NULL,0,consumer,NULL,0,&consumerID[j]);
            j++;
        }
        else if (j>=5)
        {
            PThreads[i] = CreateThread(NULL,0,producer,NULL,0,&producerID[i]);
            i++; 
 
        }
        else
        {
            int n = rand()%2;
            if (n == 0)
            {
                PThreads[i] = CreateThread(NULL,0,producer,NULL,0,&producerID[i]);
                i++;
            }
            else
            {
                CThreads[j] = CreateThread(NULL,0,consumer,NULL,0,&consumerID[j]);
                j++;
            }
        }
    }

这只是思路，结构自己整理
[解决办法]
//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 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;
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
[解决办法]
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}
#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;
}

[解决办法]
不需要循环开线程，两个就够了， 线程间不要加同步机制，一个打印生产者，一个打印消费者。就可以实现了，线程在调度时，其实也不是随机的，由于优先级相同，那么就拿时间片调度，会出现1、1、1、2、2、1、2、1、1、2、2。。。。的现象。
[解决办法]
引用:
我把线程挂起之后按照随机顺序唤醒他们，可是还是不行。

线程创建时就挂起，然后需要启动时，就启动他，其他时候是同步问题，可以记录时间戳，而不是输出到屏幕。
为每个线程维护一个变量或者列表，时间戳。
结束测试时，对各个线程的时间戳排序，即可得到各个线程，执行过程的顺序。
输出到控制台是个费时的操作，可能会改变，线程运行过程；
这个才是赵老师，经常挂到嘴边的，测不准原理，实际是人择原理。

人的参与，会改变事件的运行过程，人择原理。

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