en:docs:dos:api:int21:43:01

Note: This API call is for DOS and Win16 personality only. Use Family API for portability.

2018/09/07 05:04 · prokushev · 0 Comments

Int 21H, AH=43H, AL=01H

Version

2 and higher

Brief

“CHMOD” - SET FILE ATTRIBUTES

Family API

Input

      AX = 4301h
      CX = new file attributes (see #01420)
      DS:DX -> ASCIZ filename

Return

CF clear if successful

          AX destroyed
      CF set on error
          AX = error code (01h,02h,03h,05h) (see #01680 at AH=59h)

Macro

Notes

will not change volume label or directory attribute bits, but will change the other attribute bits of a directory (the directory bit must be cleared to successfully change the other attributes of a directory, but the directory will not be changed to a normal file as a result)

MS-DOS 4.01 reportedly closes the file if it is currently open

for security reasons, the Novell NetWare execute-only bit can never be cleared; the file must be deleted and recreated

under the FlashTek X-32 DOS extender, the filename pointer is in DS:EDX

DOS 5.0 SHARE will close the file if it is currently open in sharing-compatibility mode, otherwise a sharing violation critical error is generated if the file is currently open

DR DOS 3.41/5.0 will silently ignore attempts to change the 'directory' attribute bit

Bitfields for file attributes:

Bit(s) Description
7 shareable (Novell NetWare)
7 pending deleted files (Novell DOS, OpenDOS)
6 unused
5 archive
4 directory
3 volume label
3 execute-only (Novell NetWare)
2 system
1 hidden
0 read-only

See also

AX=4300h,AX=7143h,INT 2F/AX=110Eh

Note

2018/09/04 17:23 · prokushev · 0 Comments