Note: This API call is for DOS personality only. Use Family API for portability.
INT 21H
AH | Description | Version |
00H | Program terminate | 1.0+ |
01H | Character input | 1.0+ |
02H | Character output | 1.0+ |
03H | Auxiliary input | 1.0+ |
04H | Auxiliary output | 1.0+ |
05H | Printer output | 1.0+ |
06H | Direct console I/O | 1.0+ |
07H | Direct console input without echo | 1.0+ |
08H | Console input without echo | 1.0+ |
09H | Display string | 1.0+ |
0AH | Buffered keyboard input | 1.0+ |
0BH | Get input status | 1.0+ |
0CH | Flush input buffer and input | 1.0+ |
0DH | Disk reset | 1.0+ |
0EH | Set default drive | 1.0+ |
0FH | Open file | 1.0+ |
10H | Close file | 1.0+ |
11H | Find first file | 1.0+ |
12H | Find next file | 1.0+ |
13H | Delete file | 1.0+ |
14H | Sequential read | 1.0+ |
15H | Sequential write | 1.0+ |
16H | Create or truncate file | 1.0+ |
17H | Rename file | 1.0+ |
19H | Get default drive | 1.0+ |
1AH | Set disk transfer address | 1.0+ |
1BH | Get allocation info for default drive | 1.0+ |
1CH | Get allocation info for specified drive | 1.0+ |
1FH | Get disk parameter block for default drive | 1.0+ |
21H | Random read | 1.0+ |
22H | Random write | 1.0+ |
23H | Get file size in records | 1.0+ |
24H | Set random record number | 1.0+ |
25H | Set interrupt vector | 1.0+ |
26H | Create PSP | 1.0+ |
27H | Random block read | 1.0+ |
28H | Random block write | 1.0+ |
29H | Parse filename | 1.0+ |
2AH | Get date | 1.0+ |
2BH | Set date | 1.0+ |
2CH | Get time | 1.0+ |
2DH | Set time | 1.0+ |
2EH | Set verify flag | 1.0+ |
2FH | Get disk transfer address | 2.0+ |
30H | Get DOS version | 2.0+ |
31H | Terminate and stay resident | 2.0+ |
32H | Get disk parameter block for specified drive | 2.0+ |
33H | Extended functions | 2.0+ |
34H | Get InDOS flag pointer | 2.0+ |
35H | Get interrupt vector | 2.0+ |
36H | Get free disk space | 2.0+ |
37H | Extended functions | 2.0+ |
38H | Get or set country info | 2.0+ |
39H | Create subdirectory | 2.0+ |
3AH | Remove subdirectory | 2.0+ |
3BH | Change current directory | 2.0+ |
3CH | Create or truncate file | 2.0+ |
3DH | Open file | 2.0+ |
3EH | Close file | 2.0+ |
3FH | Read file or device | 2.0+ |
40H | Write file or device | 2.0+ |
41H | Delete file | 2.0+ |
42H | Move file pointer | 2.0+ |
43H | Get or set file attributes | 2.0+ |
44H | I/O control for devices | 2.0+ |
45H | Duplicate handle | 2.0+ |
46H | Redirect handle | 2.0+ |
47H | Get current directory | 2.0+ |
48H | Allocate memory | 2.0+ |
49H | Release memory | 2.0+ |
4AH | Reallocate memory | 2.0+ |
4BH | Execute program | 2.0+ |
4CH | Terminate with return code | 2.0+ |
4DH | Get program return code | 2.0+ |
4EH | Find first file | 2.0+ |
4FH | Find next file | 2.0+ |
50H | Set current PSP | 2.0+ |
51H | Get current PSP | 2.0+ |
52H | Get DOS internal pointers (SYSVARS) | 2.0+ |
53H | Create disk parameter block | 2.0+ |
54H | Get verify flag | 2.0+ |
55H | Create program PSP | 2.0+ |
56H | Rename file | 2.0+ |
57H | Get or set file date and time | 2.0+ |
58H | Get or set allocation strategy | 2.11+ |
59H | Get extended error info | 3.0+ |
5AH | Create unique file | 3.0+ |
5BH | Create new file | 3.0+ |
5CH | Lock or unlock file | 3.0+ |
5DH | File sharing functions | 3.0+ |
5EH | Network functions | 3.0+ |
5FH | Network redirection functions | 3.0+ |
60H | Qualify filename | 3.0+ |
61H | Reserved | 3.0+ |
62H | Get current PSP | 3.0+ |
63H | Get DBCS lead byte table pointer | 3.0+ |
64H | Set wait for external event flag | 3.2+ |
65H | Get extended country info | 3.3+ |
66H | Get or set code page | 3.3+ |
67H | Set handle count | 3.3+ |
68H | Commit file | 3.3+ |
69H | Get or set media id | 4.0+ |
6AH | Commit file | 4.0+ |
6BH | Reserved | 4.0+ |
6CH | Extended open/create file | 4.0+ |
DOS API |
Process manager | INT 20H, INT 21H: 00H, 25H, 26H, 31H, 34H, 35H, 4CH, INT 22H, INT 27H, INT 28H |
File manager | INT 25H, INT 26H, INT 21H: 0DH, 0EH, 0FH, 10H, 11H, 12H, 13H, 14H, 15H, 16H, 17H, 19H, 1AH, 1BH, 1CH, 21H, 22H, 23H, 24H, 27H, 28H, 29H, 2EH, 2FH, 32H, 3305H, 36H, 39H, 3AH, 3BH |
Character Device I/O | INT 29H, INT 21H: 01H, 02H, 03H, 04H, 05H, 06H, 07H, 08H, 09H, 0AH, 0BH, 0AH, 0CH |
Signals | INT 23H, INT 24H, INT 21H: 3300H, 3301H, 3302H |
Memory manager | |
Date and Time | INT 21H: 2AH, 2BH, 2CH, 2DH |
Misc | INT 21H: 30H, 3306H, 3700H, 3701H, 3702H, 3703H |
NLS | INT 21H: 3303H, 3304H, 3800H, 3801H |