MFC(进程间的通信,孙鑫C++第十七讲笔记整理)
有四种方法
1.剪贴板
a.创建个ClipBoard的对话框应用程序，加两EditBox和两个Button发送接收。
b.具体代码：
发送端代码：
if(OpenClipboard())
{
CString str;
HANDLE hClip;
char *pBuf;
EmptyClipboard();
GetDlgItemText(IDC_EDIT_SEND,str);
hClip=GlobalAlloc(GMEM_MOVEABLE,str.GetLength()+1);
pBuf=(char*)GlobalLock(hClip);将句柄转换为指针！
strcpy(pBuf,str);
GlobalUnlock(hClip);
SetClipboardData(CF_TEXT,hClip);
CloseClipboard();
}
接收端代码：
if(OpenClipboard())
{
if(IsClipboardFormatAvailable(CF_TEXT))
{
HANDLE hClip;
char *pBuf;
hClip=GetClipboardData(CF_TEXT);
pBuf=(char*)GlobalLock(hClip);
GlobalUnlock(hClip);
SetDlgItemText(IDC_EDIT_RECV,pBuf);
CloseClipboard();
}
}
2.匿名管道：只能在父子进程之间进行通信
a.先建一个Parent的单文档应用程序，增加“创建管道”“读取数据”“写入数据”三个菜单
b.增加成员变量HANDLE类型的hRead,hWrite，初始化变量，并在析构函数中释放句柄
c.响应菜单代码：
void CParentView::OnPipeCreate()菜单“创建管道”代码
{
// TOD Add your command handler code here
SECURITY_ATTRIBUTES sa;
sa.bInheritHandle=TRUE;
sa.lpSecurityDescriptor=NULL;
sa.nLength=sizeof(SECURITY_ATTRIBUTES);
if(!CreatePipe(&hRead,&hWrite,&sa,0))
{
MessageBox("创建匿名管道失败！");
return;
}
STARTUPINFO sui;
PROCESS_INFORMATION pi;
ZeroMemory(&sui,sizeof(STARTUPINFO));将数据清0！
sui.cb=sizeof(STARTUPINFO);
sui.dwFlags=STARTF_USESTDHANDLES;
sui.hStdInput=hRead;
sui.hStdOutput=hWrite;
sui.hStdError=GetStdHandle(STD_ERROR_HANDLE);
if(!CreateProcess("..\\Child\\Debug\\Child.exe",NULL,NULL,NULL,
TRUE,0,NULL,NULL,&sui,&pi))创建子进程
{
CloseHandle(hRead);
CloseHandle(hWrite);关闭句柄，将内核对象的使用计数减少1，这样当操作系统发现内核对象的使用计数为0时，将清除内核对象。
hRead=NULL;
hWrite=NULL;
MessageBox("创建子进程失败！");
return;
}
else
{
CloseHandle(pi.hProcess);
CloseHandle(pi.hThread);
}
}void CParentView::OnPipeRead()菜单“读取数据”代码
{
// TOD Add your command handler code here
char buf[100];
DWORD dwRead;
if(!ReadFile(hRead,buf,100,&dwRead,NULL))
{
MessageBox("读取数据失败！");
return;
}
MessageBox(buf);
}void CParentView::OnPipeWrite()菜单“写入数据”代码
{
// TOD Add your command handler code here
char buf[]="http://www.sunxin.org";
DWORD dwWrite;
if(!WriteFile(hWrite,buf,strlen(buf)+1,&dwWrite,NULL))
{
MessageBox("写入数据失败！");
return;
}
}
d.再建一个Child的单文档，在View中增加两个成员hRead和hWrite.在OnInitialUpdate()中得到句柄的值。
void CChildView::OnInitialUpdate()
{
CView::OnInitialUpdate();
// TOD Add your specialized code here and/or call the base class
hRead=GetStdHandle(STD_INPUT_HANDLE);注意这句代码！
hWrite=GetStdHandle(STD_OUTPUT_HANDLE);
} e.加菜单“读取数据”“写入数据”其代码如下：
void CChildView::OnPipeRead()
{
// TOD Add your command handler code here
char buf[100];
DWORD dwRead;
if(!ReadFile(hRead,buf,100,&dwRead,NULL))
{
MessageBox("读取数据失败！");
return;
}
MessageBox(buf);
}void CChildView::OnPipeWrite()
{
// TOD Add your command handler code here
char buf[]="匿名管道测试程序";
DWORD dwWrite;
if(!WriteFile(hWrite,buf,strlen(buf)+1,&dwWrite,NULL))
{
MessageBox("写入数据失败！");
return;
}
}
3.命名管道：还可以跨网络通信，服务器只能在win2000和NT下运行！而客户端可以在95下运行。关键函数CreateNamedPipe
a.先建一个NamedPipeSRV单文档应用程序，加菜单“创建管道”“读取数据”“写入数据”
b.在View中增加Handle变量hPipe，注意在析构函数中释放它！
c.响应菜单，创建命名管道
void CNamedPipeSrvView::OnPipeCreate()
{
// TOD Add your command handler code here
hPipe=CreateNamedPipe("\\\\.\\pipe\\MyPipe",
PIPE_ACCESS_DUPLEX | FILE_FLAG_OVERLAPPED,
0,1,1024,1024,0,NULL);
if(INVALID_HANDLE_VALUE==hPipe)
{
MessageBox("创建命名管道失败！");
hPipe=NULL;
return;
}
HANDLE hEvent;
hEvent=CreateEvent(NULL,TRUE,FALSE,NULL);
if(!hEvent)
{
MessageBox("创建事件对象失败！");
CloseHandle(hPipe);
hPipe=NULL;
return;
}
OVERLAPPED ovlap;
ZeroMemory(&ovlap,sizeof(OVERLAPPED));
ovlap.hEvent=hEvent;
if(!ConnectNamedPipe(hPipe,&ovlap))
{
if(ERROR_IO_PENDING!=GetLastError())
{
MessageBox("等待客户端连接失败！");
CloseHandle(hPipe);
CloseHandle(hEvent);
hPipe=NULL;
return;
}
}
if(WAIT_FAILED==WaitForSingleObject(hEvent,INFINITE))
{
MessageBox("等待对象失败！");
CloseHandle(hPipe);
CloseHandle(hEvent);
hPipe=NULL;
return;
}
CloseHandle(hEvent);
}void CNamedPipeSrvView::OnPipeRead()
{
// TOD Add your command handler code here
char buf[100];
DWORD dwRead;
if(!ReadFile(hPipe,buf,100,&dwRead,NULL))
{
MessageBox("读取数据失败！");
return;
}
MessageBox(buf);
}void CNamedPipeSrvView::OnPipeWrite()
{
// TOD Add your command handler code here
char buf[]="http://www.sunxin.org";
DWORD dwWrite;
if(!WriteFile(hPipe,buf,strlen(buf)+1,&dwWrite,NULL))
{
MessageBox("写入数据失败！");
return;
}
} d.再建一个NamedPipeCLT单文档工程，加菜单“连接管道”“读取数据”“写入数据”，当然别忘记成员变量hPipe的定义和初始化
e.响应菜单代码
void CNamedPipeCltView::OnPipeConnect()连接管道
{
// TOD Add your command handler code here
if(!WaitNamedPipe("\\\\.\\pipe\\MyPipe",NMPWAIT_WAIT_FOREVER))
{
MessageBox("当前没有可利用的命名管道实例！");
return;
}
hPipe=CreateFile("\\\\.\\pipe\\MyPipe",GENERIC_READ | GENERIC_WRITE,
0,NULL,OPEN_EXISTING,FILE_ATTRIBUTE_NORMAL,NULL);
if(INVALID_HANDLE_VALUE==hPipe)
{
MessageBox("打开命名管道失败！");
hPipe=NULL;
return;
}
}void CNamedPipeCltView::OnPipeRead()读取数据
{
// TOD Add your command handler code here
char buf[100];
DWORD dwRead;
if(!ReadFile(hPipe,buf,100,&dwRead,NULL))
{
MessageBox("读取数据失败！");
return;
}
MessageBox(buf);
}void CNamedPipeCltView::OnPipeWrite()写入数据
{
// TOD Add your command handler code here
char buf[]="命名管道测试程序";
DWORD dwWrite;
if(!WriteFile(hPipe,buf,strlen(buf)+1,&dwWrite,NULL))
{
MessageBox("写入数据失败！");
return;
}
}
4.邮槽，使用时应将消息长度限制在424字节以下，关键函数CreateMailSlot()
a.先建一个MailSlotSRV工程，加菜单“接收数据”
b.消息响应代码：
void CMailslotSrvView::OnMailslotRecv()菜单“接收数据”的代码
{
// TOD Add your command handler code here
HANDLE hMailslot;
hMailslot=CreateMailslot("\\\\.\\mailslot\\MyMailslot",0,
MAILSLOT_WAIT_FOREVER,NULL);
if(INVALID_HANDLE_VALUE==hMailslot)
{
MessageBox("创建油槽失败！");
return;
}
char buf[100];
DWORD dwRead;
if(!ReadFile(hMailslot,buf,100,&dwRead,NULL))
{
MessageBox("读取数据失败！");
CloseHandle(hMailslot);
return;
}
MessageBox(buf);
CloseHandle(hMailslot);
}
c.加工程MailSlotCLT,加菜单“发送数据”
d.加消息响应，添加代码，客户端也比较简单。
void CMailslotCltView::OnMailslotSend()菜单“发送数据”的代码
{
// TOD Add your command handler code here
HANDLE hMailslot;
hMailslot=CreateFile("\\\\.\\mailslot\\MyMailslot",GENERIC_WRITE,
FILE_SHARE_READ,NULL,OPEN_EXISTING,FILE_ATTRIBUTE_NORMAL,NULL);
if(INVALID_HANDLE_VALUE==hMailslot)
{
MessageBox("打开油槽失败！");
return;
}
char buf[]="http://www.sunxin.org";
DWORD dwWrite;
if(!WriteFile(hMailslot,buf,strlen(buf)+1,&dwWrite,NULL))
{
MessageBox("写入数据失败！");
CloseHandle(hMailslot);
return;
}
CloseHandle(hMailslot);
}
5.以上4种方法各有优缺点：剪贴板比较简单。邮槽是基于广播的，可以一对多发送。但只能一个发送，一个接收，要想同时发送接收，须写两次代码。
命名管道和邮槽可以进行网络通信。
剪切板
void CJieQieBanDlg::OnSend() {// TODO: Add your control notification handler code hereif(OpenClipboard())//首先要打开剪切板{CString str;HANDLE hChip;char *pBuf;EmptyClipboard();//清空剪切板GetDlgItemText(ID_FASONG,str);//获取发送数据的内容hChip=GlobalAlloc(GMEM_MOVEABLE,str.GetLength()+1);//分配空间，返回一个句柄pBuf=(char*)GlobalLock(hChip);//上锁，返回一个字符指针strcpy(pBuf,str);//复制内容GlobalUnlock(hChip);//解锁SetClipboardData(CF_TEXT,hChip);//设置剪切板的内容CloseClipboard();}}
void CJieQieBanDlg::OnRecv() {// TODO: Add your control notification handler code hereif(OpenClipboard())//打开剪切板{if(IsClipboardFormatAvailable(CF_TEXT))//判断剪切板的内容格式是否是我们需要的{HANDLE hChip;char *pBuf;hChip=GetClipboardData(CF_TEXT);//返回一个句柄pBuf=(char*)GlobalLock(hChip);//获取内容GlobalUnlock(hChip);SetDlgItemText(ID_JIESHOU,pBuf);//设置内容CloseHandle(hChip);}}}
匿名管道：
1父进程：
a添加两个CXXView成员变量HANDLE hRead,HANDLE hWrite
b构造函数赋值hRead=NULL,hWrite=NULL,析构函数if(!hRead) CloseHandle(hRead)...
c
void CParentView::OnPipeCreate() {// TODO: Add your command handler code hereSECURITY_ATTRIBUTES sa;sa.bInheritHandle=TRUE;sa.lpSecurityDescriptor=NULL;sa.nLength=sizeof(SECURITY_ATTRIBUTES);if(!CreatePipe(&hRead,&hWrite,&sa,0)){MessageBox("创建管道失败");return ;}PROCESS_INFORMATION pi;STARTUPINFO sui;ZeroMemory(&sui,sizeof(STARTUPINFO));//这一句很重要，将数据清零sui.cb=sizeof(STARTUPINFO);sui.dwFlags=STARTF_USESTDHANDLES;sui.hStdInput=hRead;sui.hStdOutput=hWrite;sui.hStdError=GetStdHandle(STD_ERROR_HANDLE);if(!CreateProcess("..\\Child\\Debug\\Child.exe",NULL,NULL,NULL,TRUE,0,NULL,NULL,&sui,&pi)){CloseHandle(hWrite);CloseHandle(hRead);hRead=NULL;hWrite=NULL;MessageBox("子进程创建失败");return ;}else{CloseHandle(pi.hProcess);CloseHandle(pi.hThread);}}
d
void CParentView::OnXieru() {// TODO: Add your command handler code herechar temp[]="hello,i am writing...";unsigned long len;if(!WriteFile(hWrite,temp,strlen(temp)+1,&len,NULL)){MessageBox("写入失败");return ;}}
e
void CParentView::OnDuqu() {// TODO: Add your command handler code herechar temp[100];unsigned long len;if(!ReadFile(hRead,temp,100,&len,NULL)){MessageBox("读取失败");return ;}MessageBox(temp);}
子进程
a,CXXVIEW中添加成员变量HANDLE hRead,HANDLE hWrite，在构造函数和析构函数进行响应的操作
bCXXView中添加虚函数OnInitialUpdate
void CChildView::OnInitialUpdate() {CView::OnInitialUpdate();// TODO: Add your specialized code here and/or call the base classhRead=GetStdHandle(STD_INPUT_HANDLE);hWrite=GetStdHandle(STD_OUTPUT_HANDLE);}
void CChildView::OnXieru() {// TODO: Add your command handler code herechar temp[]="hello,wel to my blog,i am afei";unsigned long len;if(!WriteFile(hWrite,temp,strlen(temp)+1,&len,NULL)){MessageBox("写入数据失败");return ;}}
void CChildView::OnDuqu() {// TODO: Add your command handler code herechar temp[100];unsigned long len;if(!ReadFile(hRead,temp,100,&len,NULL)){MessageBox("读取数据失败");return ;}MessageBox(temp);}
先启动父进程，然后通过父进程建立子进程，然后就能实现父子进程之间的通信了。
命名管道：（可跨网络）
1服务器端：
a,CXXView中添加成员变量HANDLE hPipe
b,
void CNamePipeSerView::OnPipeCreate() {// TODO: Add your command handler code herehPipe=CreateNamedPipe("\\\\.\\pipe\\mypipe",PIPE_ACCESS_DUPLEX|FILE_FLAG_OVERLAPPED,0,1,1024,1024,0,NULL);//要转义if(INVALID_HANDLE_VALUE==hPipe){MessageBox("命名管道创建失败");hPipe=NULL;return ;}HANDLE hEvent=CreateEvent(NULL,TRUE,FALSE,NULL);if(!hEvent){MessageBox("对象事件创建失败");return ;}OVERLAPPED oa;ZeroMemory(&oa,sizeof(OVERLAPPED));oa.hEvent=hEvent;if(!ConnectNamedPipe(hPipe,&oa)){if(ERROR_IO_PENDING!=GetLastError()){MessageBox("命名管道连接失败");CloseHandle(hEvent);CloseHandle(hPipe);hEvent=NULL;hPipe=NULL;return ;}}if(WAIT_FAILED==WaitForSingleObject(hEvent,INFINITE)){MessageBox("对象等待失败");CloseHandle(hEvent);CloseHandle(hPipe);hEvent=NULL;hPipe=NULL;return ;}}
void CNamePipeSerView::OnXieru() {// TODO: Add your command handler code herechar temp[]="hello,i am afei";unsigned long len;if(!WriteFile(hPipe,temp,strlen(temp)+1,&len,NULL)){MessageBox("写入文件失败");return ;}}
void CNamePipeSerView::OnDuqu() {// TODO: Add your command handler code herechar temp[100];unsigned long len;if(!ReadFile(hPipe,temp,100,&len,NULL)){MessageBox("读取文件失败");return ;}MessageBox(temp);}
客户端：
void CNamePipeCliView::OnLianjie() {// TODO: Add your command handler code hereif(!WaitNamedPipe("\\\\.\\pipe\\mypipe",NMPWAIT_WAIT_FOREVER)){MessageBox("没有可用的命名管道实例");return ;}hPipe=CreateFile("\\\\.\\pipe\\mypipe",GENERIC_READ|GENERIC_WRITE,0,NULL,OPEN_EXISTING,FILE_ATTRIBUTE_NORMAL,NULL);if(INVALID_HANDLE_VALUE==hPipe){MessageBox("打开管道失败");hPipe=NULL;return ;}}
void CNamePipeCliView::OnXieru() {// TODO: Add your command handler code herechar temp[]="i love C++,MFC...";unsigned long len;if(!WriteFile(hPipe,temp,strlen(temp)+1,&len,NULL)){MessageBox("写入文件失败");return ;}}
void CNamePipeCliView::OnDuqu() {// TODO: Add your command handler code herechar temp[100];unsigned long len;if(!ReadFile(hPipe,temp,100,&len,NULL)){MessageBox("读取文件失败");return ;}MessageBox(temp);}
这样就可以实现两个进程之间的通信了，
邮槽：（一对多）
1服务器端（接收数据）
void CYouCaoSerView::OnJieshou() {// TODO: Add your command handler code hereHANDLE hMail;hMail=CreateMailslot("\\\\.\\mailslot\\mymail",0,MAILSLOT_WAIT_FOREVER,NULL);if(INVALID_HANDLE_VALUE==hMail){MessageBox("创建油槽失败");return ;}char temp[200];DWORD dwlen;if(!ReadFile(hMail,temp,200,&dwlen,NULL)){CloseHandle(hMail);MessageBox("读取失败");return ;}CloseHandle(hMail);MessageBox(temp);}
2客户端：（发送数据）
void CYouCaoCView::OnFasong() {// TODO: Add your command handler code hereHANDLE hMail;hMail=CreateFile("\\\\.\\mailslot\\mymail",GENERIC_WRITE,FILE_SHARE_READ,NULL,OPEN_EXISTING,FILE_ATTRIBUTE_NORMAL,NULL);if(INVALID_HANDLE_VALUE==hMail){MessageBox("打开油槽失败");return ;}char temp[]="hello,welcome to my blog,i am afei";DWORD dwlen;if(!WriteFile(hMail,temp,strlen(temp)+1,&dwlen,NULL)){CloseHandle(hMail);MessageBox("写入数据失败");return ;}CloseHandle(hMail);}
要先打开服务器端的接收消息，这样客户端的发送消息才能打开油槽
要实现可以发送又可以接收的油槽运用程序，可以在同一个程序中，既编写客户端又编写服务器