On May 16, 2006, at 2:45 PM, Dan Stenning wrote:
Now that ive tried and used ptr, a few questions:
1) when using Addressof to point to an RB function, does the ptr
work fine
with C++ ( I presume so since its intended as a callback )
Yes.
2) can I point to class instance methods or am I limited to global
functions
in modules?
Yes, but you need to pass "self" in, like you would if you were
writing a plugin.
3) am I free to copy the pointer to an int , using casting etc ?
Yes, you can cast Ptr to Integer, and Integer to Ptr.
4) can I do integer calculations etc? Ie can I add an index to the
pointer?
Not quite -- you can add two pointers, but you can't add an integer
to a pointer. So, you can say myPtr + Ptr(1) to increment it, if
you'd like.
5) saw this in your release notes: the ability to dereference it
(ptr) with
any structure-safe type : how does this work ?
Just use the dot notation. Ie:
dim p as Ptr = someMemoryBlock
while p.UInt8 <> 0
p = p + Ptr(1)
wend
That'll loop until it finds a byte with a value of "0". Note that
autocomplete doesn't work in r2.
6) also : "There is an optional byte offset parameter" could you
explain
this ?
You can also write the above loop such as:
dim p as Ptr = someMemoryBlock
dim i as Integer
while p.UInt8(i) <> 0
i = i + 1
wend
If the offset isn't specified, it's assumed to be 0.
7) is it ok, allowable to pass/use Ptr as an argument datatype in RB
methods and functions ?
Yes... as long as those functions take that as a type :)
HTH,
Jon
--
Jonathan Johnson
[EMAIL PROTECTED]
REAL Software, Inc.
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