DosTransactNmPipe

This call performs a write followed by a read on a duplex message pipe.

Syntax

DosTransactNmPipe (Handle, InBuffer, InBufferLen, OutBuffer, OutBufferLen, BytesOut)

Parameters

Handle (HPIPE) - input

Named pipe handle returned by DosMakeNmPipe or DosOpen.

InBuffer (PBYTE) - input

Address of the buffer to write to the pipe.

InBufferLen (USHORT) - input

Number of bytes to be written.

OutBuffer (PBYTE) - output

Address of the buffer for returned data.

OutBufferLen (USHORT) - input

Maximum size, number of bytes, of returned data.

BytesOut (PUSHORT) - output

Address of the number of bytes read.

Return Code

rc (USHORT) - return

Return code descriptions are:

• 0 NO_ERROR
• 11 ERROR_BAD_FORMAT
• 230 ERROR_BAD_PIPE
• 231 ERROR_PIPE_BUSY
• 233 ERROR_PIPE_NOT_CONNECTED
• 234 ERROR_MORE_DATA

Remarks

DosTransactNmPipe is intended for use only on duplex message pipes. If this call is issued and the pipe is not a duplex message pipe, ERROR_BAD_FORMAT is returned.

This call enables you to implement transaction-oriented dialogs. DosTransactNmPipe writes the entire InBuffer to the pipe and then reads a response from the pipe into the OutBuffer. The current state of blocking/non-blocking has no effect. DosTransactNmPipe does not return until a message has been read into the OutBuffer. If the OutBuffer is too small to contain the response message, ERROR_MORE_DATA is returned, as described for DosRead.

Example Code

C Binding

#define INCL_DOSNMPIPES

USHORT  rc = DosTransactNmPipe(Handle, InBuffer, InBufferLen, OutBuffer,
                                OutBufferLen, BytesOut);

HPIPE            Handle;        /* Pipe handle */
PBYTE            InBuffer;      /* Write buffer */
USHORT           InBufferLen;   /* Write buffer length */
PBYTE            OutBuffer;     /* Read buffer (returned) */
USHORT           OutBufferLen;  /* Read buffer length */
PUSHORT          BytesOut;      /* Bytes read (returned) */

USHORT           rc;            /* return code */

MASM Binding

EXTRN  DosTransactNmPipe:FAR
INCL_DOSNMPIPES     EQU 1

PUSH   WORD    Handle        ;Pipe handle
PUSH@  OTHER   InBuffer      ;Write buffer
PUSH   WORD    InBufferLen   ;Write buffer length
PUSH@  OTHER   OutBuffer     ;Read buffer (returned)
PUSH   WORD    OutBufferLen  ;Read buffer length
PUSH@  WORD    BytesOut      ;Bytes read (returned)
CALL   DosTransactNmPipe

Returns WORD