Windows共享内存

Windows共享内存可以让两个进程对同一块内存进行读写。
以下有2个进程，a.cpp生成A进程，b.cpp生成b进程。那么a进程将不停地读名为"Global\\MyFileMappingObject"的共享内存块，而b进程不停地写名为"Global\\MyFileMappingObject"的共享内存块。从而实现IPC。

//a.cpp
#include <windows.h>
#include <string.h>
#include <string>
#include <iostream>
#include <tchar.h>
using namespace std;

#define BUF_SIZE 256
TCHAR szName[]=TEXT("Global\\MyFileMappingObject");    //指向同一块共享内存的名字

int main(int argc, char *argv[])
{
HANDLE hMapFile;
LPCTSTR pBuf;

hMapFile = CreateFileMapping(
INVALID_HANDLE_VALUE,    // use paging file
NULL,                    // default security
PAGE_READWRITE,          // read/write access
0,                       // maximum object size (high-order DWORD)
BUF_SIZE,                // maximum object size (low-order DWORD)
szName);                 // name of mapping object

if (hMapFile == NULL)
{
_tprintf(TEXT("Could not create file mapping object (%d).\n"),
GetLastError());
return 1;
}
pBuf = (LPTSTR) MapViewOfFile(hMapFile,   // handle to map object
FILE_MAP_ALL_ACCESS, // read/write permission
0,
0,
BUF_SIZE);

if (pBuf == NULL)
{
_tprintf(TEXT("Could not map view of file (%d).\n"),
GetLastError());

CloseHandle(hMapFile);

return 1;
}
//从main开始至此，A B process代码一样，都是获取名为"Global\\MyFileMappingObject"的共享内存的指针

//以下代码，A不停地读共享内存pBuf
while(1)
{
cout<<pBuf<<endl;
cout<<"A process: hit keyboard to receive from B process"<<endl;
getchar();
}

UnmapViewOfFile(pBuf);
CloseHandle(hMapFile);
return 0;
}

//b.cpp
#include <iostream>
#include <Windows.h>
#include <tchar.h>
using namespace std;

#define BUF_SIZE 256
TCHAR szName[]=TEXT("Global\\MyFileMappingObject");    //指向同一块共享内存的名字

int main()
{
HANDLE hMapFile;
LPCTSTR pBuf;

hMapFile = CreateFileMapping(
INVALID_HANDLE_VALUE,    // use paging file
NULL,                    // default security
PAGE_READWRITE,          // read/write access
0,                       // maximum object size (high-order DWORD)
BUF_SIZE,                // maximum object size (low-order DWORD)
szName);                 // name of mapping object

if (hMapFile == NULL)
{
_tprintf(TEXT("Could not create file mapping object (%d).\n"),
GetLastError());
return 1;
}
pBuf = (LPTSTR) MapViewOfFile(hMapFile,   // handle to map object
FILE_MAP_ALL_ACCESS, // read/write permission
0,
0,
BUF_SIZE);

if (pBuf == NULL)
{
_tprintf(TEXT("Could not map view of file (%d).\n"),
GetLastError());

CloseHandle(hMapFile);

return 1;
}
//从main开始至此，A B process代码一样，都是获取名为"Global\\MyFileMappingObject"的共享内存的指针

//以下代码，B不停写共享内存pBuf
while(1)
{
TCHAR s[BUF_SIZE];
cout<<"B process: plz input sth. to be transfered to A process."<<endl;
cin>>s;
memcpy((PVOID)pBuf, s, BUF_SIZE);
}
}