INT 21 - DOS 4.0 - EXTENDED OPEN/CREATE                    

Input

DOS1 N DOS3 N

DOS4

Y DOS5 Y

Output

AX

6Ch 00h File Handle / Error Code AX

BX

 Open Mode     BX

CX

 File Attributes Action Taken CX

DX

 Action Flag     DX

DS:SI

 ASCIIZ File Name Set if Error CF

 

Open Mode
Bit Dec Hex  Description
0 1 0001h  Access: 000 = Read Only
             001 = Write Only
             010 = Read / Write
1 2 0002h
2 4 0004h
3 8 0008h  Reserved
4 16 0010h  Compatibility: 000 = Compatibility
                       001 = Deny All
                       010 = Deny Write
                       011 = Deny Read
                       100 = Deny None
5 32 0020h
6 64 0040h
7 128 0080h  Not passed to Child
8 256 0100h  Reserved
9 512 0200h
10 1024 0400h
11 2048 0800h
12 4096 1000h
13 8192 2000h  Return error i.s.o. INT 24h
14 16384 4000h  Auto commit on Write
15 32768 8000h  Reserved
 
Action Flag
Bit Dec Hex  Description
0 1 0001h  Exists: 0000 = Fail
            0001 = Open
            0010 = Replace
1 2 0002h
2 4 0004h
3 8 0008h
4 16 0010h  Not Exists: 0000 = Fail
                  0001 = Create
5 32 0020h
6 64 0040h
7 128 0080h
8 256 0100h  Reserved
9 512 0200h
10 1024 0400h
11 2048 0800h
12 4096 1000h
13 8192 2000h
14 16384 4000h
15 32768 8000h
Action Taken:

        01h = File existed and was opened
        02h = File did not exist, created
        03h = File existed, was replaced

See Also File Attributes Error Codes


Copyright © 1985 to 2022 Beta Systems                            Last modified: Wednesday, January 05, 2022 .