请教c++,生产者与消费者的问题

[u014449693]

#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
而且

[u014449693]

大牛们快来啊，求你们了，自己顶一下

[u014449693]

而且对上面个程序加断点后，程序输出竟然不一样

[赵4老师]

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;
}

[jmppok]

多线程，打断点后，当前线程阻塞。其他线程还是在执行的。 所以在不同地方打断点，出现的结果可能不一样。 至于开始就有三个产品，可能是因为调试的问题。 你先启动了两个生产线程，三个消费线程。 生产产品前Sleep 2000 ， 生产后sleep 1000 消费前Sleep 1000 ， 消费后sleep 1000 按理说应该消费的快。 但是你5个线程又竞争的同一个互斥量，这个问题就不好说了。

[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文件、……这些方法都不行！ 写日志到文件参考3楼。