c++,生产者消费者问题

u014449693 2014-05-14 11:03:08
#include <iostream>
#include <stdlib.h>
#include <STDIO.H>
#include <windows.h>

using namespace std;

typedef int semaphore; /* 信号量是一种特殊的整型变量 */
const int SIZE_OF_BUFFER = 5 ; //缓冲区长度
const unsigned short PRODUCERS_COUNT = 2; //生产者的个数
const unsigned short CONSUMERS_COUNT = 3; //消费者的个数

DWORD producers[PRODUCERS_COUNT] ; //生产者线程的标识符
DWORD consumers[CONSUMERS_COUNT] ;//消费者线程的标识符

const unsigned short THREADS_COUNT = PRODUCERS_COUNT+CONSUMERS_COUNT; //总的线程数

/**
*定义信号量
*/
HANDLE mutex ; //互斥信号量
HANDLE full ; //表示放有产品的缓冲区数,其初值为0
HANDLE empty ; //表示可供使用的缓冲区数,其初值为N

/**
*定义共享缓冲区
*/
semaphore buffer[SIZE_OF_BUFFER];

/**
*定义生产者和消费者使用的指针
*/
int in = 0 ;
int out = 0 ;

int productNum = 0 ;

DWORD WINAPI Producer(LPVOID) ;
DWORD WINAPI Consumer(LPVOID) ;

int main(int argc, char *argv[])
{
//创建Mutex和Semaphore
mutex = CreateMutex(NULL,FALSE,NULL);
full = CreateSemaphore(NULL,0,SIZE_OF_BUFFER,NULL);
empty = CreateSemaphore(NULL,SIZE_OF_BUFFER,SIZE_OF_BUFFER,NULL);


HANDLE PVThreads[THREADS_COUNT]; //各线程的handle

//创建生产者线程
for (int i=0;i<PRODUCERS_COUNT;i++){
PVThreads[i] = CreateThread(NULL,0,Producer,NULL,0,&producers[i]);
if (PVThreads[i] == NULL) break;
}
//创建消费者线程
for (int i=0;i<CONSUMERS_COUNT;i++){
PVThreads[PRODUCERS_COUNT+i]
=CreateThread(NULL,0,Consumer,NULL,0,&consumers[i]);
if (PVThreads[i]==NULL) break;
}

bool isContinue = true ;
while(isContinue)
{
if(getchar()){ //按回车后终止程序运行
isContinue = false;
}
}
system("PAUSE");
return 0;
}

void enBuffer(int pos)
{
cout<<"正在生产产品..."<<endl ;
Sleep(2000) ;
buffer[pos] = -1 ;
productNum++ ;
cout<<"生产完成! 已生产"<<productNum<<"个产品,并将新产品放在了缓冲区位置:"<<pos<<endl ;
}

void deBuffer(int pos)
{
cout<<"正在消费产品..."<<endl ;
Sleep(1000) ;
buffer[pos] = -2 ;
productNum-- ;
cout<<"已消费在缓冲区位置:"<<pos<<"的产品,缓冲区剩余空间:"<<SIZE_OF_BUFFER-productNum<<endl ;
cout<<endl ;
}

/**
*生产者
*/
DWORD WINAPI Producer(LPVOID lpParam )
{
while(1)
{
WaitForSingleObject(empty,INFINITE); // P(empty) 生产者信号量 -1
WaitForSingleObject(mutex,INFINITE); // P(mutex) 获取线程间互斥信号
enBuffer(in) ;
Sleep(1000) ;
in = (in+1)%SIZE_OF_BUFFER ;
ReleaseMutex(mutex); // V(mutex) 释放线程间互斥信号
ReleaseSemaphore(full,1,NULL); // V(full) 消费者信号量 +1

}
return 0;
}

/**
*消费者
*/
DWORD WINAPI Consumer(LPVOID lpPara)
{
while(1)
{
WaitForSingleObject(full,INFINITE)== WAIT_ABANDONED ; //P(full) 消费者信号量-1
WaitForSingleObject(mutex,INFINITE); //P(mutex) 获得线程间互斥信号
deBuffer(out) ;
Sleep(1000) ;
out = (out+1)%SIZE_OF_BUFFER ;
ReleaseMutex(mutex); //V(mutex) 释放线程间互斥信号
ReleaseSemaphore(empty,1,NULL); //V(empty) 生产者信号量+1

}
return 0;
}
就是在上面的程序中,运行起来时,为什么为
怎么会先有三个生产产品,后面是消费过程,后面就是一个生产过程与消费过程交替出现
还有, WaitForSingleObject(full,INFINITE)== WAIT_ABANDONED ; //P(full) 消费者信号量-1 中WAIT_ABANDONED 啥意思
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赵4老师 2014-05-15
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《Windows核心编程》 Synchronization Functions The following functions are used in synchronization. CancelWaitableTimer CreateEvent CreateMutex CreateSemaphore CreateWaitableTimer DeleteCriticalSection EnterCriticalSection GetOverlappedResult InitializeCriticalSection InitializeCriticalSectionAndSpinCount InterlockedCompareExchange InterlockedDecrement InterlockedExchange InterlockedExchangeAdd InterlockedIncrement LeaveCriticalSection MsgWaitForMultipleObjects MsgWaitForMultipleObjectsEx OpenEvent OpenMutex OpenSemaphore OpenWaitableTimer PulseEvent QueueUserAPC ReleaseMutex ReleaseSemaphore ResetEvent SetCriticalSectionSpinCount SetEvent SetWaitableTimer SignalObjectAndWait TimerAPCProc TryEnterCriticalSection WaitForMultipleObjects WaitForMultipleObjectsEx WaitForSingleObject WaitForSingleObjectEx
赵4老师 2014-05-15
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先学会别人是怎么做到正确的;再研究自己是怎么不正确地做的。 代码功能归根结底不是别人帮自己看或讲解或注释出来的;而是被自己静下心来花足够长的时间和精力亲自动手单步或设断点或对执行到某步获得的中间结果显示或写到日志文件中一步一步分析出来的。 提醒:再牛×的老师也无法代替学生自己领悟和上厕所! 单步调试和设断点调试是程序员必须掌握的技能之一。
u014449693 2014-05-14
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能不能帮我解释下我的程序,谢谢
赵4老师 2014-05-14
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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
#ifdef WIN32
    #pragma warning(disable:4996)
#endif
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#ifdef WIN32
    #include <windows.h>
    #include <process.h>
    #include <io.h>
    #define  MYVOID             void
    #define  vsnprintf          _vsnprintf
#else
    #include <unistd.h>
    #include <sys/time.h>
    #include <pthread.h>
    #define  CRITICAL_SECTION   pthread_mutex_t
    #define  MYVOID             void *
#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 WIN32
void Lock(CRITICAL_SECTION *l) {
    EnterCriticalSection(l);
}
void Unlock(CRITICAL_SECTION *l) {
    LeaveCriticalSection(l);
}
void sleep_ms(int ms) {
    Sleep(ms);
}
#else
void Lock(CRITICAL_SECTION *l) {
    pthread_mutex_lock(l);
}
void Unlock(CRITICAL_SECTION *l) {
    pthread_mutex_unlock(l);
}
void sleep_ms(int ms) {
    usleep(ms*1000);
}
#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}
#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;
}
MYVOID 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_ms(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_ms(1);
            } else {
                sleep_ms(1000);
            }
            if (No_Loop) break;//
            wc++;
            if (wc>3600) Log("%03d %d==wc>3600!\n",cn,wc);
        }
        if (No_Loop) break;//
    }
#ifndef WIN32
    pthread_exit(NULL);
#endif
}
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;
}
MYVOID 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_ms(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_ms(1000);
            if (No_Loop) break;//
            wc++;
            if (wc>3600) Log("%03d %d==wc>3600!\n",cn,wc);
        }
        if (No_Loop) break;//
    }
#ifndef WIN32
    pthread_exit(NULL);
#endif
}
int main() {
#ifdef WIN32
    InitializeCriticalSection(&cs_log);
    InitializeCriticalSection(&cs_HEX );
    InitializeCriticalSection(&cs_BBB );
#else
    pthread_t threads[2];
    int threadsN;
    int rc;
    pthread_mutex_init(&cs_log,NULL);
    pthread_mutex_init(&cs_HEX,NULL);
    pthread_mutex_init(&cs_BBB,NULL);
#endif
    Log("Start===========================================================\n");

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

#ifdef WIN32
    _beginthread((void(__cdecl *)(void *))thdA,0,(void *)1);
    _beginthread((void(__cdecl *)(void *))thdB,0,(void *)2);
#else
    threadsN=0;
    rc=pthread_create(&(threads[threadsN++]),NULL,thdA,(void *)1);if (rc) Log("%d=pthread_create %d error!\n",rc,threadsN-1);
    rc=pthread_create(&(threads[threadsN++]),NULL,thdB,(void *)2);if (rc) Log("%d=pthread_create %d error!\n",rc,threadsN-1);
#endif

    if (!access("No_Loop",0)) {
        remove("No_Loop");
        if (!access("No_Loop",0)) {
            No_Loop=1;
        }
    }
    while (1) {
        sleep_ms(1000);
        if (No_Loop) break;//
        if (!access("No_Loop",0)) {
            No_Loop=1;
        }
    }
    sleep_ms(3000);
    Log("End=============================================================\n");
#ifdef WIN32
    DeleteCriticalSection(&cs_BBB );
    DeleteCriticalSection(&cs_HEX );
    DeleteCriticalSection(&cs_log);
#else
    pthread_mutex_destroy(&cs_BBB);
    pthread_mutex_destroy(&cs_HEX);
    pthread_mutex_destroy(&cs_log);
#endif
    return 0;
}

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