ConnectNamedPipe

ConnectNamedPipe is a function in the Windows API used to wait for a client process to connect to an instance of a named pipe. Named pipes are a form of inter-process communication (IPC) that allows two or more processes to communicate over a pipe. The ConnectNamedPipe function is typically used in server applications that create named pipes to handle client connections.

The function takes two parameters: a handle to the named pipe instance and a pointer to an OVERLAPPED structure. The OVERLAPPED structure is used for asynchronous I/O operations. If the function is called with a NULL pointer for the OVERLAPPED structure, it operates synchronously, blocking until a client connects or an error occurs. If an OVERLAPPED structure is provided, the function operates asynchronously, returning immediately and allowing the server to perform other tasks while waiting for a connection.

Upon successful connection, the function returns a nonzero value. If the function fails, it returns zero, and the GetLastError function can be called to retrieve the error code. Common error codes include ERROR_PIPE_CONNECTED, which indicates that a client has already connected to the pipe, and ERROR_NO_DATA, which indicates that the pipe is being closed.

ConnectNamedPipe is part of the Windows API and is available in Windows NT and later versions of Windows. It is commonly used in server applications that need to handle multiple client connections, such as remote procedure call (RPC) servers and network services. The function is typically used in conjunction with other named pipe functions, such as CreateNamedPipe and DisconnectNamedPipe, to manage the lifecycle of a named pipe instance.