WaitNamedPipe

The WaitNamedPipe function waits until either a time-out interval elapses or an instance of the specified named pipe is available for connection (that is, the pipe's server process has a pending ConnectNamedPipe operation on the pipe).

BOOL WaitNamedPipe(
  LPCTSTR lpNamedPipeName,  // pipe name
  DWORD nTimeOut            // time-out interval
);

Parameters

lpNamedPipeName

[in] Pointer to a null-terminated string that specifies the name of the named pipe. The string must include the name of the computer on which the server process is executing. A period may be used for the servername if the pipe is local. The following pipe name format is used:

\\servername\pipe\pipename

nTimeOut

[in] Specifies the number of milliseconds that the function will wait for an instance of the named pipe to be available. You can used one of the following values instead of specifying a number of milliseconds.

Value	Meaning
NMPWAIT_USE_DEFAULT_WAIT	The time-out interval is the default value specified by the server process in the CreateNamedPipe function.
NMPWAIT_WAIT_FOREVER	The function does not return until an instance of the named pipe is available.

Return Values

If an instance of the pipe is available before the time-out interval elapses, the return value is nonzero.

If an instance of the pipe is not available before the time-out interval elapses, the return value is zero. To get extended error information, call GetLastError.

Remarks

If no instances of the specified named pipe exist, the WaitNamedPipe function returns immediately, regardless of the time-out value.

If the function succeeds, the process should use the CreateFile function to open a handle to the named pipe. A return value of TRUE indicates that there is at least one instance of the pipe available. A subsequent CreateFile call to the pipe can fail, because the instance was closed by the server or opened by another client.

Requirements

  Windows NT/2000: Requires Windows NT 3.1 or later.
  Windows 95/98: Requires Windows 95 or later.
  Header: Declared in Winbase.h; include Windows.h.
  Library: Use Kernel32.lib.
  Unicode: Implemented as Unicode and ANSI versions on Windows NT/2000.

See Also

Pipes Overview, Pipe Functions, CallNamedPipe, ConnectNamedPipe, CreateFile, CreateNamedPipe