[英]C++: Implementing Named Pipes using the Win32 API
I'm trying to implement named pipes in C++, but either my reader isn't reading anything, or my writer isn't writing anything (or both). 我正在尝试用C ++实现命名管道,但要么我的读者不读任何东西,要么我的作者不写任何东西(或两者兼而有之)。 Here's my reader:
这是我的读者:
int main()
{
HANDLE pipe = CreateFile(GetPipeName(), GENERIC_READ, 0, NULL, OPEN_EXISTING, FILE_FLAG_OVERLAPPED, NULL);
char data[1024];
DWORD numRead = 1;
while (numRead >= 0)
{
ReadFile(pipe, data, 1024, &numRead, NULL);
if (numRead > 0)
cout << data;
}
return 0;
}
LPCWSTR GetPipeName()
{
return L"\\\\.\\pipe\\LogPipe";
}
And here's my writer: 这是我的作家:
int main()
{
HANDLE pipe = CreateFile(GetPipeName(), GENERIC_WRITE, 0, NULL, OPEN_EXISTING, FILE_FLAG_OVERLAPPED, NULL);
string message = "Hi";
WriteFile(pipe, message.c_str(), message.length() + 1, NULL, NULL);
return 0;
}
LPCWSTR GetPipeName()
{
return L"\\\\.\\pipe\\LogPipe";
}
Does that look right? 那看起来不错吗? numRead in the reader is always 0, for some reason, and it reads nothing but 1024 -54's (some weird I character).
由于某种原因,阅读器中的numRead始终为0,并且它只读取1024 -54(我有些奇怪的字符)。
Solution: 解:
Reader (Server): 读者(服务器):
while (true)
{
HANDLE pipe = CreateNamedPipe(GetPipeName(), PIPE_ACCESS_INBOUND | PIPE_ACCESS_OUTBOUND , PIPE_WAIT, 1, 1024, 1024, 120 * 1000, NULL);
if (pipe == INVALID_HANDLE_VALUE)
{
cout << "Error: " << GetLastError();
}
char data[1024];
DWORD numRead;
ConnectNamedPipe(pipe, NULL);
ReadFile(pipe, data, 1024, &numRead, NULL);
if (numRead > 0)
cout << data << endl;
CloseHandle(pipe);
}
Writer (client): 作家(客户):
HANDLE pipe = CreateFile(GetPipeName(), GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING, 0, NULL);
if (pipe == INVALID_HANDLE_VALUE)
{
cout << "Error: " << GetLastError();
}
string message = "Hi";
cout << message.length();
DWORD numWritten;
WriteFile(pipe, message.c_str(), message.length(), &numWritten, NULL);
return 0;
The server blocks until it gets a connected client, reads what the client writes, and then sets itself up for a new connection, ad infinitum. 服务器阻塞,直到它获得连接的客户端,读取客户端写入的内容,然后无限制地为自己设置新连接。 Thanks for the help, all!
谢谢大家的帮助!
You must use CreateNamedPipe()
to create the server end of a named pipe. 您必须使用
CreateNamedPipe()
来创建命名管道的服务器端。 Be sure to specify a non-zero buffer size, zero (documented by MSDN as 'use system default buffer size') doesn't work. 请务必指定非零缓冲区大小,零(由MSDN记录为“使用系统默认缓冲区大小”)不起作用。 MSDN has decent samples for a multi-threaded client&server.
MSDN为多线程客户端和服务器提供了不错的示例 。
A named pipe client can open the named pipe with CreateFile
-- but the named pipe server needs to use CreateNamedPipe
to create the named pipe. 命名管道客户端可以使用
CreateFile
打开命名管道 - 但命名管道服务器需要使用CreateNamedPipe
来创建命名管道。 After it's created the named pipe, the server uses ConnectNamedPipe
to wait for a client to connect. 在创建命名管道后,服务器使用
ConnectNamedPipe
等待客户端连接。 Only after the client has connected should the server do a blocking read like your call to ReadFile
. 只有在客户端连接后 ,服务器才会执行阻塞读取,就像调用
ReadFile
。
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