前言

windows 许多应用程序会在运行的时候创建一些数据，并需要将这些数据传输给其他进程，或者和其他进程共享某块内存。

可以使用 CreateFileMapping 并在使用时候第一个参数传入 INVALID_HANDLE_VALUE 。告诉系统创建的文件映射对象的物理存储器不是磁盘上的文件，而是从页交换文件中调拨物理存储器(就是从内存上分配共享内存的意思)。

使用例子

进程B 向共享内存写数据

//写进程
#include <iostream>
#include <windows.h>
#include <process.h>
#include <stdlib.h>
#include <conio.h>
#include <tchar.h>
#include <string.h>
using namespace std;
#define BUF_SIZE 256
TCHAR szName[] = TEXT("Global\\MyFileMappingObject");

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
		BUF_SIZE,			  //maximum object size (low order
		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;
	}
	HANDLE rst = CreateEvent(NULL, FALSE, FALSE, L"ttt");

	while (1)
	{
		TCHAR s[BUF_SIZE];
		cout << "B process : plz input sth.to be transfered to A process" << endl;;
		wcin >> s;
		memcpy((PVOID)pBuf, s, BUF_SIZE);
		SetEvent(rst);
	}
	UnmapViewOfFile(pBuf);
	CloseHandle(hMapFile);
}

进程A：向共享内存读数据

//读进程
#include <iostream>
#include <windows.h>
#include <process.h>
#include <stdlib.h>
#include <conio.h>
#include <tchar.h>
#include <string.h>
using namespace std;
#define BUF_SIZE 256
TCHAR szName[] = TEXT("Global\\MyFileMappingObject");

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
		BUF_SIZE,			  //maximum object size (low order
		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;
	}
	HANDLE rst = CreateEvent(NULL, FALSE, FALSE, TEXT("ttt"));
	while (1)
	{
		WaitForSingleObject(rst, INFINITE);
		
		cout << "A process : receive some sth from B process" << endl;
		wcout << pBuf << endl;
		//_getch();
	}
	UnmapViewOfFile(pBuf);
	CloseHandle(hMapFile);
}

运行

进程B写入数据

同时进程A收到数据