DosQNmPHandState

This call returns information for a named pipe's specific handle state.

DosQNmPHandState

(Handle, PipeHandleState)

Handle (HPIPE) - input

Handle of the named pipe returned by DosMakeNmPipe or DosOpen.
PipeHandleState (PUSHORT) - output
Address of the named pipe handle state:

Bit

Description
15
Blocking; pipe is defined as follows:

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 (value is 1) changes this behavior as follows:

- DosRead returns immediately with BytesRead = 0 (as defined in DosRead) if no data is available.
- DosWrite returns immediately with BytesWritten = 0 (as defined in DosWrite) if insufficient buffer space is available in the pipe, or the entire data area is transferred.
14
Server or requester end; end-point of named pipe shown as follows:

0 = Handle is the client end of a named pipe.

1 = Handle is the server (requester) end of a named pipe.

13-12
Reserved.
11-10
Type of named pipe:

00 = Pipe is a byte stream pipe.

01 = Pipe is a message stream pipe.

9-8
Read mode:

00 = Read pipe as a byte stream.

01 = Read pipe as a message stream.

7-0
Instance count; 8-bit count to control pipe instances. When making the first instance of a named pipe, this field specifies how many instances can be created. Instances are as follows:
Value
Definition
1
This can be the only instance (pipe is unique).
-1
The number of instances is unlimited.
0
Reserved value.
rc (USHORT) - return
Return code descriptions are:
• NO_ERROR 230
  ERROR_BAD_PIPE
  233
  ERROR_PIPE_NOT_CONNECTED
  Remarks

  At the serving end, the values returned by DosQNmPHandState are those originally established by DosMakeNmPipe or a subsequent DosSetNmPHandState. The values returned by the client end are those originally established by DosOpen or a subsequent DosSetNmPHandState.

  ---

  [Back: DosQHandType]
  [Next: DosQNmPipeInfo]