by size you mean the size of the structure? ouch... the size of the structure
is exactly 0x2c including the reserved stuff. if you don't include the
reserved stuff, it's 0x24.
the first operation should be a calloc to allocate the structure, which zeros
the structure memory first before the call, and zero the flags (which includes
CF).
with djgpp, they additionally instruct you to zero sp, and ss, so that go32
will
automatically alloc a stack (lest you end up with garbage).
with the thinking that if the OS doesn't support this function whatsoever and
totally blows it, you will get a zero back your original stuff, and of course
the zeroing of the structure leaves you with the size member coming back with
what? zero. thus it is less than 0x24 (the size of the structure minus the
reserved area) and thus an error. and of course of it is greater than 0x2c
(the
size of the structure including the reserved space), it is suspect as well.
good catch.
I set CF to 0 before I started, and I got 0 when I ended. windows xp. xp
totally blew the function call.
I set the entire structure to 0's before I started, and I got 0's back. but
then again that's windows xp. it would be interesting to see what happens on
other OS's...
now I need a guinea pig freedos FAT32 machine to test my df program on...
________________________________
From: dos386 <dos...@gmail.com>
To: freedos-devel@lists.sourceforge.net
Sent: Mon, February 14, 2011 12:08:20 AM
Subject: Re: [Freedos-devel] documentation for FreeDOS filesystem or other
programming functions/interfaces?
> RBIL is pretty much it (right?
> http://www.delorie.com/djgpp/doc/rbinter/id/40/32.htm
NO, see above.
> I am hoping to implement some sort of fallback mechanism into the program
> so that if int 21h, 7303h fails, I have int 21h, 36h to fall back on
> but I need to know exactly how to detect failure
See above: clear buffer, set "size" to $30, set flag(C) to 1, call INT
$21 / AX=$7303, if ((flag(C)=1) or ("size" < $24) or ("size">$2C))
then /* F**K, do fallback to AH=$36 */ ...
--
~~~ wow ~~~
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The ultimate all-in-one performance toolkit: Intel(R) Parallel Studio XE:
Pinpoint memory and threading errors before they happen.
Find and fix more than 250 security defects in the development cycle.
Locate bottlenecks in serial and parallel code that limit performance.
http://p.sf.net/sfu/intel-dev2devfeb
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