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From: ewout@topcat.commodore.com (Ewout Walraven)
Newsgroups: comp.sys.amiga.programmer
Subject: Re: SetFont(rp, &MyFont) eats 24 bytes of fast memory - Found: 2.0 bug
Message-ID: <20011@cbmvax.commodore.com>
Date: 21 Mar 91 13:38:20 GMT
References: <1991Mar20.220218.25195@watdragon.waterloo.edu> <1991Mar21.044941.15171@watdragon.waterloo.edu>
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ccplumb@rose.uwaterloo.ca (Colin Plumb) writes:

>Well, a bit of poking around in the 2.0 includes discovered the answer.

>It's not a message port; it's just that 2.0 usurped the pointer to
>point to a TextFontExtension struct.  The includes I have say it's
>a 20 byte struct, but I'm losing 24... it might have been extended
>since I saw it, or those mysterious GfxFree/GfxNew/GfxAssociate functions
>I saw doing some bookkeeping for me, but in any case I don't know how to
>free it safely.  More digging, and aha!  There are ExtendFont and
>StripFont functions that look significant...

>So now my cleanup code, after doing a SetFont() back to the old, saved
>rp->Font pointer for paranoia's sake, tests to see if the tf_Extension
>(a.k.a. tf_message.mn_ReplyPort) pointer holds non-NULL, and if so,
>calls the 2.0-specific StripFont() function on my TextFont structure.

>This seems to work, without memory leakage, on both 1.3 and 2.0.
>So, I think I've found an (admittedly minor) backward-compatibility bug
>between 2.0 and 1.3.  Perhaps some 2.0-knowledgeable (or at least,
>autodoc-posessing!) person could tell me if this ad hoc solution is
>indeed correct?

Yes it is. Using SetFont() on in-code TextFonts will loose 24 bytes, unless
you call StripFont(). That V36 buglet and how to deal with it are
documented in the Autodocs.

>Thanks!
>-- 
>	-Colin