🚀 go-pugleaf

In article <root.658802253@tirith.UUCP> root@tirith.UUCP (Root) writes:
>Noteworthy detail: You allocate the memory for the file handle, and pass
>it to the filehandler, which will initialize its contents.  You must
>free this memory as well after you close the file.

	NOTE: if you must do this (instead of calling Open()), then as
the original Dos Tech Ref Manual states, you MUST initialize all fields
to 0, except fh_Pos and fh_End, which must be -1.  I advise against
allocating filehandles if there is a way to avoid it.  Copying the contents
of filehandles is right out.

	There was one totally unused field in a FileHandle that I have
laid retroactive claim to (since it never did anything, and as mentioned
above you had to initialize it to 0).  This is fh_Link, soon to be known
as fh_Flags.

>Now, if you'll all carefully consult dosextens.h, you'll next ask "what
>about those fh_Buffer and related fields - how are they used?".  My best
>answer is that beyond the fh_Task and fh_Arg1 fields, the filesystem is
>not supposed to change anything.  And the application program isn't
>supposed to change anything period.  So I presume they're dead space,
>left over from BCPL and TriPos.  (My money says ed and/or edit use
>them though). 

	All BCPL buffered IO uses them, as does the shell, etc.  Under 2.0,
all the buffered input/output routines use them.  Don't touch.  BTW, fh_Arg2
belongs to the filesystem also, though in reality it's almost useless since
it's never passed anywhere.

-- 
Randell Jesup, Keeper of AmigaDos, Commodore Engineering.
{uunet|rutgers}!cbmvax!jesup, jesup@cbmvax.cbm.commodore.com  BIX: rjesup  
Common phrase heard at Amiga Devcon '89: "It's in there!"