DosCallNmPipe

Description

This call performs a "procedure call" transaction using a message pipe.

Syntax

 DosCallNmPipe

    (FileName, InBuffer, InBufferLen, OutBuffer, OutBufferLen, BytesOut, TimeOut)

Parameters

FileName (PSZ) - input

Address of the ASCIIZ name of the pipe to be opened. Pipes are named \PIPE\FileName.

InBuffer (PBYTE) - input

Address of the buffer to write to the pipe.

InBufferLen (USHORT) - input

Number of bytes to be written.

OutBuffer (PBYTE) - input/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 variable where the system returns the number of bytes actually read (returned).

TimeOut (ULONG) - input

Maximum time to wait for pipe availability.

Return Code

rc (USHORT) - return

Return code descriptions are:

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

Remarks

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

This call has the combined effect on a named pipe of DosOpen, DosTransactNmPipe, and DosClose. It provides an efficient means of implementing local and remote procedure-call (RPC) interfaces between processes.

Example Code

C Binding

#define INCL_DOSNMPIPES

USHORT  rc = DosCallNmPipe(FileName, InBuffer, InBufferLen, OutBuffer,
                             OutBufferLen, BytesOut, TimeOut);

PSZ              FileName;      /* Pipe name */
PBYTE            InBuffer;      /* Write buffer address */
USHORT           InBufferLen;   /* Write buffer length */
PBYTE            OutBuffer;     /* Read buffer address */
USHORT           OutBufferLen;  /* Read buffer length *
PUSHORT          BytesOut;      /* Bytes read (returned) */
ULONG            TimeOut;       /* Maximum wait time */

USHORT           rc;            /* return code */

MASM Binding

EXTRN  DosCallNmPipe:FAR
INCL_DOSNMPIPES     EQU 1

PUSH@  ASCIIZ  FileName      ;Pipe name
PUSH@  OTHER   InBuffer      ;Write buffer
PUSH   WORD    InBufferLen   ;Write buffer length
PUSH@  OTHER   OutBuffer     ;Read buffer
PUSH   WORD    OutBufferLen  ;Read buffer length
PUSH@  WORD    BytesOut      ;Bytes read (returned)
PUSH   DWORD   TimeOut       ;Maximum wait time
CALL   DosCallNmPipe

Returns WORD