win32共享内存简单实例

//win32ShareMemoryClient.cpp

#include <Windows.h>
#include <iostream>

using namespace std;

int main()
{
HANDLE hMutex      = NULL;
HANDLE hFileMapping   = NULL;
LPVOID lpShareMemory  = NULL;
HANDLE hServerWriteOver = NULL;
HANDLE hClientReadOver = NULL;

hMutex = OpenMutex(MUTEX_ALL_ACCESS, FALSE, "SM_Mutex");
if (NULL == hMutex)
{
if (ERROR_FILE_NOT_FOUND == GetLastError())
{
cout << "OpenMutex fail: file not found!" << endl;
}
else
{
cout << "OpenMutex fail:" << GetLastError() << endl;
}

goto CLIENT_SHARE_MEMORY_END;
}

//一旦互斥对象处于有信号状态，则该函数返回
if (WaitForSingleObject(hMutex, 5000) != WAIT_OBJECT_0)
{
cout << "WaitForSingle error:" << GetLastError() << endl;
goto CLIENT_SHARE_MEMORY_END;
}

//open share memory
hFileMapping = OpenFileMapping(FILE_MAP_ALL_ACCESS,
FALSE,
"ShareMemoryTest");
if (NULL == hFileMapping)
{
cout << "OpenFileMapping" << GetLastError() << endl;
goto CLIENT_SHARE_MEMORY_END;
}

lpShareMemory = MapViewOfFile(hFileMapping,
FILE_MAP_ALL_ACCESS,
0,
0,
0);
if (NULL == lpShareMemory)
{
cout << "MapViewOfFile " << GetLastError() << endl;
goto CLIENT_SHARE_MEMORY_END;
}

//read and write data
hServerWriteOver = CreateEvent(NULL,
TRUE,
FALSE,
"ServerWriteOver");

hClientReadOver = CreateEvent(NULL,
TRUE,
FALSE,
"ClientReadOver");

if (NULL == hServerWriteOver || NULL == hClientReadOver)
{
cout << "CreateEvent " << GetLastError() << endl;
goto CLIENT_SHARE_MEMORY_END;
}

char p = 0;
char* q = (char*)lpShareMemory;
do
{
if (!SetEvent(hClientReadOver))
{
goto CLIENT_SHARE_MEMORY_END;
}

if (WaitForSingleObject(hServerWriteOver, INFINITE) != WAIT_OBJECT_0)
{
goto CLIENT_SHARE_MEMORY_END;
}

p = q[0];
putchar(p);
if (!ResetEvent(hServerWriteOver))
{
goto CLIENT_SHARE_MEMORY_END;
}
} while (p != '\n');

CLIENT_SHARE_MEMORY_END:
if (NULL != hServerWriteOver)	CloseHandle(hServerWriteOver);
if (NULL != hClientReadOver)		CloseHandle(hClientReadOver);
if (NULL != lpShareMemory)		UnmapViewOfFile(lpShareMemory);
if (NULL != hFileMapping)			CloseHandle(hFileMapping);
if (NULL != hMutex)					ReleaseMutex(hMutex);

return 0;
}

//win32ShareMemoryServer.cpp

#include <Windows.h>
#include <iostream>

using namespace std;

int main()
{
HANDLE hMutex = NULL;
HANDLE hFileMapping = NULL;
LPVOID lpShareMemory = NULL;
HANDLE hServerWriteOver = NULL;
HANDLE hClientReadOver = NULL;

//create share memory
hFileMapping = CreateFileMapping( INVALID_HANDLE_VALUE, //映射文件的句柄, 若设为0xFFFFFFFF(即：INVALID_HANDLE_VALUE)则创建一个进程间共享的对象
NULL, //安全属性
PAGE_READWRITE, //保护方式
0, //对象的大小
1024*1024,
"ShareMemoryTest"); // 映射文件名，即共享内存的名称
if (NULL == hFileMapping)
{
cout << "CreateFileMapping fail:" << GetLastError() << endl;
goto SERVER_SHARE_MEMORY_END;
}

lpShareMemory = MapViewOfFile( hFileMapping,
FILE_MAP_ALL_ACCESS,
0,
0,
0);
if (NULL == lpShareMemory)
{
cout << "MapViewOfFile" << GetLastError() << endl;
goto SERVER_SHARE_MEMORY_END;
}

//创建互斥对象，初始时不占有该互斥量，互斥对象名字是"SM_Mutex"
hMutex = CreateMutex(NULL, FALSE, "SM_Mutex");
if (NULL == hMutex || ERROR_ALREADY_EXISTS == GetLastError())
{
cout << "CreateMutex" << GetLastError() << endl;
goto SERVER_SHARE_MEMORY_END;
}

//事件对象就像一个开关：它只有两种状态---开和关。当一个事件处于”开”状态，我们称其为”有信号”否则称为”无信号”。
//send data
hServerWriteOver = CreateEvent(NULL, //采用默认属性
TRUE, //创建的Event是自动复位还是人工复位.如果true,人工复位, 一旦该Event被设置为有信号,则它一直会等到ResetEvent()API被调用时才会恢复 为无信号.
FALSE, //初始状态,true有信号,false无信号
"ServerWriteOver"); //事件对象的名称
hClientReadOver = CreateEvent(NULL,
TRUE,
FALSE,
"ClientReadOver");

if (NULL == hServerWriteOver || NULL == hClientReadOver)
{
cout << "CreateEvent " << GetLastError() << endl;
goto SERVER_SHARE_MEMORY_END;
}

char p = 0;
char* q = (char*)lpShareMemory;
do
{
p = getchar();
//在事件对象生成后，必须调用WaitForSingleObject来让线程进入等待状态
//当等待的时间超过该值后无信号同步对象仍处于”无信号”状态，线程不再等待， WaitForSingleObject函数会返回。
//如果想要线程一直等待，请把该参数设为INFINITE（该值等于0xffffffff)。
if (WaitForSingleObject(hClientReadOver, 5*1000) != WAIT_OBJECT_0)
{
goto SERVER_SHARE_MEMORY_END;
}

q[0] = p;
if (!ResetEvent(hClientReadOver)) goto SERVER_SHARE_MEMORY_END;//把指定的事件对象设置为无信号状态
if (!SetEvent(hServerWriteOver)) goto SERVER_SHARE_MEMORY_END;//把指定的事件对象设置为有信号状态
} while (p != '\n');

SERVER_SHARE_MEMORY_END:
//release share memory
if (NULL != hServerWriteOver) CloseHandle(hServerWriteOver);
if (NULL != hClientReadOver) CloseHandle(hClientReadOver);
if (NULL != lpShareMemory) UnmapViewOfFile(lpShareMemory);
if (NULL != hFileMapping) CloseHandle(hFileMapping);
if (NULL != hMutex) ReleaseMutex(hMutex);

return 0;
}