c/c++函数指针

2021-12-09 06:50:56

2014-03-29 星期六 10:31:48

c/c++函数指针demo

1、funcptr.hh
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//funcptr demo
 
class CFuncPtr  //:public CThread
{
public:
  static CFuncPtr* createNew(int chn=0, int type=0);
   
public:
    static void *(*funcentry[8])(void *para);   //demo,没继承CThread,就这样了
    static void *ThreadEntry_00(void *para);
    static void *ThreadEntry_01(void *para);
    static void *ThreadEntry_10(void *para);
    static void *ThreadEntry_11(void *para);
    static void *ThreadEntry_20(void *para);
    static void *ThreadEntry_21(void *para);
    static void *ThreadEntry_30(void *para);
    static void *ThreadEntry_31(void *para);
    static void assignfunc();
 
protected:
    CFuncPtr(int chn,int type);
    ~CFuncPtr();
 
protected:
    void ThreadProc();
 
private:
    int m_chn;
    int m_type;
    int m_cnt;
    pthread_t m_pid;   
};
 
typedef  int (CFuncPtr::*EntryFuncPtr)(void *para);
2、funcptr.cpp
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#include <iostream> 
#include <iterator>
#include <vector>
#include <algorithm>
#include <utility> 
#include <string> 
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <sys/select.h>
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <errno.h>
#include <pthread.h>
 
#include "funcptr.hh"
 
#define TRY_EVALUATE_POINTER(pointer, value) do{\
    if(pointer)\
    {\
        *(pointer) = value;\
    }\
}while(0)
 
typedef void *(*ThreadEntryPtrType)(void *);
 
int CreateNormalThread(ThreadEntryPtrType entry, void *para, pthread_t *pid)
{
    pthread_t ThreadId;
    pthread_attr_t attr;
 
    pthread_attr_init(&attr);  
    pthread_attr_setscope(&attr, PTHREAD_SCOPE_SYSTEM);
    pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
    if(pthread_create(&ThreadId, &attr, entry, para) == 0)
    {
        pthread_attr_destroy(&attr);
        TRY_EVALUATE_POINTER(pid, ThreadId);
         
        return 0;
    }
 
    pthread_attr_destroy(&attr);
 
    return -1;
}
 
void mSleep(unsigned int  MilliSecond)
{
    struct timeval time;
    time.tv_sec = MilliSecond / 1000;           //seconds
    time.tv_usec = MilliSecond * 1000 % 1000000;//microsecond
    select(0, NULL, NULL, NULL, &time);
}
 
#define ENTYBODY()  {\
    CFuncPtr *pthis = (CFuncPtr *)para;\
    \
    if(!pthis)\
    {\
        exit(1);\
    }\
    pthis->ThreadProc();\
    return NULL;\
}
 
void *CFuncPtr::ThreadEntry_01(void *para)
{
    printf("line %d, %s, entry\n", __LINE__, __func__);
    ENTYBODY();
}
void *CFuncPtr::ThreadEntry_10(void *para)
{
    printf("line %d, %s, entry\n", __LINE__, __func__);
    ENTYBODY();
}
void *CFuncPtr::ThreadEntry_11(void *para)
{
    printf("line %d, %s, entry\n", __LINE__, __func__);
    ENTYBODY();
}
void *CFuncPtr::ThreadEntry_20(void *para)
{
    printf("line %d, %s, entry\n", __LINE__, __func__);
    ENTYBODY();
}
void *CFuncPtr::ThreadEntry_21(void *para)
{
    printf("line %d, %s, entry\n", __LINE__, __func__);
    ENTYBODY();
}
void *CFuncPtr::ThreadEntry_30(void *para)
{
    printf("line %d, %s, entry\n", __LINE__, __func__);
    ENTYBODY();
}
void *CFuncPtr::ThreadEntry_31(void *para)
{
    printf("line %d, %s, entry\n", __LINE__, __func__);
    ENTYBODY();
}
 
 
//CFuncPtr
 
//static void *(*funcentry[8])(void *para); //demo,没继承CThread,就这样了
 
void* (*CFuncPtr::funcentry[8])(void *para);
 
void CFuncPtr::assignfunc()
{
    CFuncPtr::funcentry[0] = CFuncPtr::ThreadEntry_00;
    CFuncPtr::funcentry[1] = CFuncPtr::ThreadEntry_01;
    CFuncPtr::funcentry[2] = CFuncPtr::ThreadEntry_10;
    CFuncPtr::funcentry[3] = CFuncPtr::ThreadEntry_11;
    CFuncPtr::funcentry[4] = CFuncPtr::ThreadEntry_20;
    CFuncPtr::funcentry[5] = CFuncPtr::ThreadEntry_21;
    CFuncPtr::funcentry[6] = CFuncPtr::ThreadEntry_30;
    CFuncPtr::funcentry[7] = CFuncPtr::ThreadEntry_31;
}
 
//仅demo
CFuncPtr::CFuncPtr(int chn, int type)
    : m_chn(chn)
    , m_type(type)
{
    EntryFuncPtr pEntryFunc;
 
    int num = m_chn*2 + m_type;
    CreateNormalThread(CFuncPtr::funcentry[num], (void *)this, &m_pid);
    printf("line %d, %s, num(%d)\n", __LINE__, __func__, num);
 
}
CFuncPtr::~CFuncPtr()
{
 
}
 
void *CFuncPtr::ThreadEntry_00(void *para)
{
    printf("line %d, %s, entry\n", __LINE__, __func__);
    CFuncPtr *pthis = (CFuncPtr *)para;
     
    if(!pthis)
    {
        exit(1);
    }
 
    pthis->ThreadProc();
    return NULL;
}
 
void CFuncPtr::ThreadProc()
{  
    printf("line %d, %s, entry\n", __LINE__, __func__);
    while(1)
    {
        mSleep(20);
        if(++m_cnt == 100)
        {  
            m_cnt = 0;
            printf("line %d, %s, running, chn(%d), type(%d)\n",
                __LINE__, __func__, m_chn, m_type);
        }
    }
}
 
CFuncPtr* CFuncPtr::createNew(int chn, int type)
{
    return new CFuncPtr(chn, type);
}
 
//g++ funcptr.cpp -lpthread
int main (int argc,char *argv[])
{ 
    //char* estr = "Hello,ni hao!";
    //std::cout<<"The count of CExample: "<<estr<<std::endl;
    CFuncPtr::assignfunc();
     
    CFuncPtr *pCFuncPtr[4][2];
    int chn,type;
    for(chn=0; chn<2; ++chn)
    {
        for(type=0; type<2; ++type)
        {
            pCFuncPtr[chn][type] = CFuncPtr::createNew(chn, type);
        }
    }
 
    while(1)
    {
        mSleep(200);
    };
     
    return 0;
}

 

相信通过这个demo，大家对函数指针应该有了比较清晰的认知。

 

c/c++函数指针,布布扣,bubuko.com

c/c++函数指针

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