利用存储映射实现线程间通信-优快云博客

本文通过创建互斥量和内存映射文件，演示了在Windows环境下如何实现线程间的通信。示例代码中，两个线程分别负责写入和读取共享内存，并通过互斥量保证数据同步。

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#include "stdafx.h"
#include "stdio.h"
#include "afxmt.h"

int i=50;
HANDLE hMutex1;
//CCriticalSection Cmysection;
HANDLE g_hMutexShrMem; // Used for hare memory write&read

bool WriteSharedMemory(char* pName,void *pData, UINT nSize)
{
if(g_hMutexShrMem == NULL){
g_hMutexShrMem = CreateMutex(NULL, FALSE, "ShrMem");
}

WaitForSingleObject(g_hMutexShrMem, INFINITE);

HANDLE hFileMapping = CreateFileMapping( INVALID_HANDLE_VALUE, NULL, PAGE_READWRITE, 0, nSize, pName );

if ( hFileMapping == NULL ) {
ReleaseMutex(g_hMutexShrMem);

return false;
}

void *pMapView = MapViewOfFile( hFileMapping, FILE_MAP_WRITE, 0, 0, nSize );

if ( pMapView == NULL ) {
ReleaseMutex( g_hMutexShrMem );

return false;
}

//Clear share memory
memset( pMapView, 0, nSize );

//write to memory
memcpy( pMapView, pData, nSize );

UnmapViewOfFile( pMapView );

ReleaseMutex( g_hMutexShrMem );

return true;
}
bool ReadSharedMemory( char* pName, void *pData, UINT nSize )
{
if(g_hMutexShrMem == NULL){
g_hMutexShrMem = CreateMutex(NULL, FALSE, "ShrMem");
}

WaitForSingleObject( g_hMutexShrMem, INFINITE );

HANDLE hFileMapping = OpenFileMapping( FILE_MAP_ALL_ACCESS, FALSE, pName );

    if ( hFileMapping == NULL )
{
  ReleaseMutex( g_hMutexShrMem );
        return false;
}

void *pMapView = MapViewOfFile( hFileMapping, FILE_MAP_ALL_ACCESS, 0, 0, nSize );

    if ( pMapView == NULL )
{
  ReleaseMutex( g_hMutexShrMem );
        return false;
}

// Read from share memory
memcpy( pData, pMapView, nSize );

// 共有メモリの内容をクリアする
memset( pMapView, 0, nSize );

UnmapViewOfFile( pMapView );

ReleaseMutex( g_hMutexShrMem );

return true;
}

DWORD WINAPI clientthread(LPVOID lpparam)
{
// while(true){
  ::WaitForSingleObject(hMutex1,INFINITE);
//  if(i>0){
//  ::Sleep(100);
//  printf("thread %d is runing        ",num);
// printf("%d/n",i);
// i=i-1;}
//  else{
//  break;
//  }
  int *p;
  int m;
  p = &m;
  *p=10;
  char a[10]="rongning";
//  a[0]='r';
//  a[1]='o';
//       a[2]='4';
  char* tt;
  tt=a;
WriteSharedMemory("NM3200",tt,10);
::ReleaseMutex(hMutex1);
// }

return 0;
}

DWORD WINAPI clientthread2(LPVOID lpparam)
{
//     int num=(int)lpparam;
// while(true){
//
  ::WaitForSingleObject(hMutex1,INFINITE);
//  if(i>0){
//
//  ::Sleep(100);
//  printf("thread %d is runing        ",num);
//  printf("%d/n",i);
//     i=i-1;
//  }
//  else{
//  break;
//  }
char ct[12];
ReadSharedMemory("NM3200",ct,12);
  printf(ct);

// for(int i=0;i<10;i++){
// printf("%c",ct[i]);
// }

::ReleaseMutex(hMutex1);
// }

return 0;
}

int main(int argc, char* argv[])
{
    int num = 1;
    HANDLE hthread1,hthread2;
    DWORD dwthreadid;
    //char szBuff[MAX_PATH];

    hthread1=CreateThread(NULL,0,clientthread,(LPVOID)num,0,&dwthreadid);
//    if(hthread1==NULL)
//    {
//        printf("fail55/n");
//    }

    hthread2=CreateThread(NULL,0,clientthread2,(LPVOID)(num+1),0,&dwthreadid);
//    if(hthread2==NULL)
//    {
//        printf("fail55/n");
//    }
//    gets(szBuff);

hMutex1 = CreateMutex(NULL,true,"mutext1");

::ReleaseMutex(hMutex1);
    Sleep(7000);
    CloseHandle(hthread1);
    CloseHandle(hthread2);
    return 0;
}