Tandy 1000 Programmer's Reference Guide

Chapter 1 I System Calls
Duplicate a File Handle
Function Call
45H
Takes an already opened file handle and returns a new handle
that refers
to the same file at the same position.
Entry Conditions:
AH = 45H
BX
= file handle to duplicate
E xi t Conditions :
Carry set:
Carry not set:
Error Returns:
AX = 6
AX = error code
AX = new file handle
Invalid Handle. The handle passed in BX is not cur-
rently open.
Too many open files. There were no free handles
available in the current process or the internal system
tables were full.
AX = 4
Example:
DUP equ 45H
mov bx, handle
mov ah, Dup
int 21 H
120

Tandy 1000 Specifications

General

Processor	Intel 8088
Processor Speed	4.77 MHz
RAM	128 KB (expandable to 640 KB)
Operating System	MS-DOS 2.11
Manufacturer	Tandy Corporation
Release Year	1984
Storage	Single or double 5.25" floppy disk drive (360 KB), optional hard drive
Sound	Tandy 3-voice sound
Ports	Parallel, Serial
Graphics	CGA (Color Graphics Adapter)
Graphics Modes	320x200, 640x200