DosMakePipe

This call creates a pipe.

Syntax

DosMakePipe (ReadHandle, WriteHandle, PipeSize) 

Parameters

ReadHandle (PHFILE) - output

Address of the read handle of the pipe.

WriteHandle (PHFILE) - output

Address of the write handle of the pipe.

PipeSize (USHORT) - input

Storage size, in bytes, to reserve for the pipe.

Return Code

rc (USHORT) - return

Return code descriptions are:

• 0 NO_ERROR
• 4 ERROR_TOO_MANY_OPEN_FILES
• 8 ERROR_NOT_ENOUGH_MEMORY
• 109 ERROR_BROKEN_PIPE

Remarks

Pipes are mechanisms used within a closely related group of processes. There are no control, permission mechanisms, or checks performed on operations to pipes.

When there is insufficient space in a pipe for the data being written, a requesting thread blocks until enough data is removed to allow the write request to be satisfied. If the PipeSize parameter is 0, then the pipe is created with a default size of 512 bytes.

When all users close the handles, a pipe is deleted. If two processes are communicating by a pipe and the process reading the pipe ends, the next write gets the "ERROR_BROKEN_PIPE" error code.

Example Code

C Binding

#define INCL_DOSQUEUES

USHORT  rc = DosMakePipe(ReadHandle, WriteHandle, PipeSize);

PHFILE           ReadHandle;    /* Address to put read handle (returned) */
PHFILE           WriteHandle;   /* Address to put write handle (returned) */
USHORT           PipeSize;      /* Size to reserve for the pipe */

USHORT           rc;            /* return code */

MASM Binding

EXTRN  DosMakePipe:FAR
INCL_DOSQUEUES      EQU 1

PUSH@  WORD    ReadHandle    ;Read handle (returned)
PUSH@  WORD    WriteHandle   ;Write handle (returned)
PUSH   WORD    PipeSize      ;Size to reserve for the pipe
CALL   DosMakePipe

Returns WORD