DosQNmPHandState

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

Syntax

DosQNmPHandState (Handle, PipeHandleState)

Parameters

Handle (HPIPE) - input

Handle of the named pipe returned by DosMakeNmPipe or DosOpen.

PipeHandleState (PUSHORT) - output

Address of the named pipe handle state:

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:

1 - This can be the only instance (pipe is unique).

-1 - The number of instances is unlimited.

0 - Reserved value.

Return Code

rc (USHORT) - return

Return code descriptions are:

• 0 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.

Bindings

C

#define INCL_DOSNMPIPES

USHORT  rc = DosQNmPHandState(Handle, PipeHandleState);

HPIPE   Handle;          /* Pipe handle */
PUSHORT PipeHandleState; /* Pipe handle state */

USHORT  rc;              /* return code */

MASM

EXTRN  DosQNmPHandState:FAR
INCL_DOSNMPIPES     EQU 1

PUSH   WORD    Handle          ;Pipe handle
PUSH@  WORD    PipeHandleState ;Pipe handle state (returned)
CALL   DosQNmPHandState

Returns WORD