Table des matières
INT 0x21 - 0x3d - Open File or Device Using Handle
Request/Call:
| reg | value | descr |
|---|---|---|
| AH | 0x3d | |
| AL | open mode (see below) | |
| DS:DX | pointer to ASCIIZ file name |
open mode
| Bit | Descr |
|---|---|
| 0-2 | Access Mode (see below) |
| 3 | reserved, always 0 |
| 4-6 | sharing mode (DOS 3.1+) |
| 7 | 1 : private, 0: inheritable (DOS 3.1+) |
Access Mode
| bits | Descr |
|---|---|
| 000 | Read |
| 001 | Write |
| 010 | Read & Write |
sharing mode
| bits | descr. |
|---|---|
| 000 | compatibility mode (exclusive) |
| 001 | Deny others read/write access |
| 010 | deny others write access |
| 011 | deny others read access |
| 100 | full access permitted to all |
Return:
CF is cleared : success
| reg | descr |
|---|---|
| AX | File Handle |
CF is set: error
| reg | descr |
|---|---|
| AX | error code (see DOS Error Code) |
Notes & Comments
- will open normal, hidden and system files
- file pointer is placed at beginning of file