Category: DOS kernel
INT 21 - DOS 2+ - "OPEN" - OPEN EXISTING FILE AH = 3Dh AL = access and sharing modes (see #01402) DS:DX -> ASCIZ filename CL = attribute mask of files to look for (server call only) Return: CF clear if successful AX = file handle CF set on error AX = error code (01h,02h,03h,04h,05h,0Ch,56h) (see #01680 at AH=59h) Notes: file pointer is set to start of file if SHARE or a network is loaded, the file open may fail if the file is already open, depending on the combination of sharing modes (see #01403,#01404) file handles which are inherited from a parent also inherit sharing and access restrictions files may be opened even if given the hidden or system attributes under the FlashTek X-32 DOS extender, the pointer is in DS:EDX DR DOS checks the system password or explicitly supplied password at the end of the filename (following a semicolon) against the reserved field in the directory entry before allowing access sharing modes are only effective on local drives if SHARE is loaded BUG: Novell DOS 7 SHARE v1.00 would refuse file access in the cases in #01403 marked with [1] (read-only open of a read-only file which had previously been opened in compatibility mode); this was fixed in SHARE v1.01 of 09/29/94 SeeAlso: AH=0Fh,AH=3Ch,AX=4301h,AX=5D00h,INT 2F/AX=1116h,INT 2F/AX=1226h