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Table 1636

Format of SHARE.EXE hooks (DOS 3.1-6.00):
Offset	Size	Description	)
(offsets from first system file table--pointed at by ListOfLists+04h)
-3Ch	DWORD	pointer to FAR routine for ???
		Note: not called by MS-DOS 3.3, set to 0000h:0000h by
			SHARE 3.3+
-38h	DWORD	pointer to FAR routine called on opening file
		on call, internal DOS location points at filename
		  (see #01687 at AX=5D06h)
		Return: CF clear if successful
			CF set on error
			    AX = DOS error code (24h)
				  (see #01680 at AH=59h/BX=0000h)
		Note: SHARE directly accesses DOS-internal data to get name of
			file just opened
-34h	DWORD	pointer to FAR routine called on closing file
		ES:DI -> system file table
		Note: does something to every Record Lock Record for file
-30h	DWORD	pointer to FAR routine to close all files for given computer
		(called by AX=5D03h)
-2Ch	DWORD	pointer to FAR routine to close all files for given process
		(called by AX=5D04h)
-28h	DWORD	pointer to FAR routine to close file by name
		(called by AX=5D02h)
		DS:SI -> DOS parameter list (see #01686 at AX=5D00h)
		   DPL's DS:DX -> name of file to close
		Return: CF clear if successful
			CF set on error
			    AX = DOS error code (03h)
				  (see #01680 at AH=59h/BX=0000h)
-24h	DWORD	pointer to FAR routine to lock region of file
		call with BX = file handle
			  ---DOS 3.x---
			  CX:DX = starting offset
			  SI:AX = size
			  ---DOS 4.0+ ---
			  DS:DX -> lock range
					DWORD start offset
					DWORD size in bytes
		Return: CF set on error
			    AL = DOS error code (21h) (see #01680 at AH=59h)
		Note: not called if file is marked as remote
-20h	DWORD	pointer to FAR routine to unlock region of file
		call with BX = file handle
			  ---DOS 3.x---
			  CX:DX = starting offset
			  SI:AX = size
			  ---DOS 4.0+ ---
			  DS:DX -> lock range
					DWORD start offset
					DWORD size in bytes
		Return: CF set on error
			    AL = DOS error code (21h) (see #01680 at AH=59h)
		Note: not called if file is marked as remote
-1Ch	DWORD	pointer to FAR routine to check if file region is locked
		call with ES:DI -> system file table entry for file
			CX = length of region from current position in file
		Return: CF set if any portion of region locked
			    AX = 0021h
-18h	DWORD	pointer to FAR routine to get open file list entry
		(called by AX=5D05h)
		call with DS:SI -> DOS parameter list (see #01686 at AX=5D00h)
			DPL's BX = index of sharing record
			DPL's CX = index of SFT in SFT chain of sharing rec
		Return: CF set on error or not loaded
			    AX = DOS error code (12h) (see #01680 at AH=59h)
			CF clear if successful
			    ES:DI -> filename
			    CX = number of locks owned by specified SFT
			    BX = network machine number
			    DX destroyed
-14h	DWORD	pointer to FAR routine for updating FCB from SFT???
		call with DS:SI -> unopened FCB
			  ES:DI -> system file table entry
		Return: BL = C0h???
		Note: copies following fields from SFT to FCB:
		   starting cluster of file	  0Bh	 1Ah
		   sharing record offset	  33h	 1Ch
		   file attribute		  04h	 1Eh
-10h	DWORD	pointer to FAR routine to get first cluster of FCB file ???
		call with ES:DI -> system file table entry
			  DS:SI -> FCB
		Return: CF set if SFT closed or sharing record offsets
				mismatched
			CF clear if successful
			    BX = starting cluster number from FCB
-0Ch	DWORD	pointer to FAR routine to close file if duplicate for process
		DS:SI -> system file table
		Return: AX = number of handle in JFT which already uses SFT
		Note: called during open/create of a file
		Note: if SFT was opened with inheritance enabled and sharing
			mode 111, does something to all other SFTs owned by
			same process which have the same file open mode and
			sharing record
-08h	DWORD	pointer to FAR routine for closing file
		Note: closes various handles referring to file most-recently
			opened
-04h	DWORD	pointer to FAR routine to update directory info in related SFT
		  entries
		call with ES:DI -> system file table entry for file (see #01641)
			  AX = subfunction (apply to each related SFT)
				00h: update time stamp (offset 0Dh) and date
				     stamp (offset 0Fh)
				01h: update file size (offset 11h) and starting
				     cluster (offset 0Bh).  Sets last-accessed
				     cluster fields to start of file if file
				     never accessed
				02h: as function 01h, but last-accessed fields
				     always changed
				03h: do both functions 00h and 02h
		Note: follows ptr at offset 2Bh in system file table entries
		Note: NOP if opened with no-inherit or via FCB
Notes:	most of the above hooks (except -04h, -14h, -18h, and -3Ch) assume
	  either that SS=DOS DS or SS=DS=DOS DS and directly access
	  DOS-internal data
	sharing hooks are not supported by DR DOS 5-6; they appear to be
	  supported by Novell DOS 7, with a segment of 0000h indicating the
	  DOS data segment
SeeAlso: #01637,#01638


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