Important Notice

The pages on this site contain documentation for very old MS-DOS software, purely for historical purposes. If you're looking for up-to-date documentation, particularly for programming, you should not rely on the information found here, as it will be woefully out of date.

                                             ◄Up► ◄Contents► ◄Index► ◄Back►
──────────────────────────────────────────────────────────────────────────────
 
     Interrupt 21h
 
     See also: Other MS-DOS Interrupts
 
     Function     Name
 
     00h          Terminate Process
     01h          Character Input with Echo
     02h          Character Output
     03h          Auxiliary Input
     04h          Auxiliary Output
     05h          Printer Output
     06h          Direct Console I/O
     07h          Unfiltered Character Input without Echo
     08h          Character Input without Echo
     09h          Display String
     0Ah          Buffered Keyboard Input
     0Bh          Check Input Status
     0Ch          Flush Input Buffer, Then Input
     0Dh          Disk Reset
     0Eh          Select Disk
     0Fh          Open File (FCB)
     10h          Close File (FCB)
     11h          Find First File (FCB)
     12h          Find Next File (FCB)
     13h          Delete File (FCB)
     14h          Sequential Read (FCB)
     15h          Sequential Write (FCB)
     16h          Create File (FCB)
     17h          Rename File (FCB)
     19h          Get Current Drive
     1Ah          Set Data Transfer Area (DTA) Address
     1Bh          Get Drive Data
     1Ch          Get Drive Data
     21h          Random Read (FCB)
     22h          Random Write (FCB)
     23h          Get File Size (FCB)
     24h          Set Relative Record Number (FCB)
     25h          Set Interrupt Vector
     26h          Create New Program Segment Prefix (PSP)
     27h          Random Block Read (FCB)
     28h          Random Block Write (FCB)
     29h          Parse Filename (FCB)
     2Ah          Get Date
     2Bh          Set Date
     2Ch          Get Time
     2Dh          Set Time
     2Eh          Set Verify Flag
     2Fh          Get DTA Address
     30h          Get MS-DOS Version Number
     31h          Terminate and Stay Resident
     33h          Get or Set Break Flag
     34h          Get address of InDOS Flag
     35h          Get Interrupt Vector
     36h          Get Drive Allocation Information
     38h          Get or Set Country Information
     39h          Create Directory
     3Ah          Delete Directory
     3Bh          Set Current Directory
     3Ch          Create File
     3Dh          Open File
     3Eh          Close File
     3Fh          Read File or Device
     40h          Write to File or Device
     41h          Delete File
     42h          Set File Pointer (current location in file)
     43h          Get or Set File Attributes
     44h          IOCTL (I/O Control)
     45h          Duplicate Handle
     46h          Redirect Handle
     47h          Get Current Directory
     48h          Allocate Memory Block
     49h          Release Memory Block
     4Ah          Resize Memory Block
     4Bh          Execute Program (EXEC)
     4Ch          Terminate Process with Return Code
     4Dh          Get Return Code
     4Eh          Find First File
     4Fh          Find Next File
     50h          Set Program Segment Prefix (PSP) Address
     51h          Get Program Segment Prefix (PSP) Address
     54h          Get Verify Flag
     56h          Rename File
     57h          Get or Set File Date and Time
     58h          Get or Set Allocation Strategy
     59h          Get Extended Error Information
     5Ah          Create Temporary File
     5Bh          Create New File
     5Ch          Lock or Unlock Region of File
     5Eh          Get Machine Name, Get or Set Printer Setup
     5Fh          Device Reallocation
     62h          Get PSP Address
     63h          Get Lead Byte Table
     65h          Get Extended Country Information
     66h          Get or Set Code Page
     67h          Set Handle Count (sets maximum number of files)
     68h          Commit File (forces buffer to be written out)
     6Ch          Extended Open File (opens, creates, or replaces file)
     5D0Ah        Set Extended Error Information
                                    -♦-