DosSetNmPHandState

Bindings:  C, MASM 

This call sets the read and blocking modes of a named pipe. 

 DosSetNmPHandState      (Handle, PipeHandleState) 
 

 Handle (HPIPE) - input 
    Handle of the named pipe returned by DosMakeNmPipe or DosOpen. 

 PipeHandleState (USHORT) - input 
    Named pipe handle state, consists of the following bit fields: 

    Bit       Description 

    15        Blocking flag: 

              0 = Reads /Writes block if no data available. 

              1 = Reads/Writes return immediately if no data available. 

              Reads normally block until at least partial data can be 
              returned. Writes by default block until all bytes requested 
              have been written.  Non-blocking mode (B = 1) changes this 
              behavior as follows: 

       DosRead 
                 Returns BytesRead = 0 if no data is available. 
       DosWrite 
                 Returns BytesWritten = 0 if there is not enough buffer 
                 space available in the pipe.  Otherwise, the entire data 
                 area is transferred. 

    14-10     Reserved and must be set to zero. 

    9-8       Read Mode flag: 

              00 = Read pipe as byte stream. 

              01 = Read pipe as a message stream. 

    7-0       Reserved and must be set to zero. 

 rc (USHORT) - return 
    Return code descriptions are: 

    0         NO_ERROR 
    87        ERROR_INVALID_PARAMETER 
    230       ERROR_BAD_PIPE 
    231       ERROR_PIPE_BUSY 
    233       ERROR_PIPE_NOT_CONNECTED 
 
 Remarks 

 The read mode and blocking/non-blocking mode of a named pipe can be 
 changed.  The pipe mode can not be changed to non-blocking when another 
 thread is blocked on an I/O to the same end of the pipe.