Int 2F/AX=1000h

SHARE - INSTALLATION CHECK

AX = 1000h

Return:
AL = status 00h not installed, OK to install 01h not installed, not OK to install FFh installed

Notes: Supported by OS/2 v1.3+ compatibility box, which always returns AL=FFh. If DOS 4.01 SHARE was automatically loaded, file sharing is in an inactive state (due to the undocumented /NC flag used by the autoload code) until this call is made. DR DOS 5.0 SHARE 1.00 only checks for AH=10h and in this case does not chain to a previous handler, DR DOS 6.0 SHARE 1.02+ properly chains for any values other than AX=1000h and the private FDOS hook AX=1001h. However, under DR PalmDOS and Novell DOS 7+, the SHARE 2.00+ only tests for the AX=1000h install check, since it no longer uses AX=1001h to hook into the system.. DOS 5+ chains to the previous handler if AL <> 00h on entry. Windows Enhanced mode hooks this call and reports that SHARE is installed even when it is not

BUGS: Values of AL other than 00h put DOS 3.x SHARE into an infinite loop

(08E9:
OR  AL,AL
08EB:
JNZ 08EB) <- the buggy instruction (DOS 3.3).
Values of AL other than described here put PC-DOS 4.00 into the same
loop (the buggy instructions are the same)

See Also: AX=1080h - INT 21/AH=52h - INT 21/AX=4457h/DX=FFFFh

Category: File Manipulation - Int 2Fh - S

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