Re: malloc problem in C++
Jason wrote:
"Victor Bazarov" <v.Abazarov@comAcast.net> wrote in message
news:fan5sq$eba$1@news.datemas.de...
Jason wrote:
But it _does_ allocate memory, as in it locks memory on the heap for
that specific pointer?
Sure. If you look at some popular implementations of 'new' and
'new[]', you'll see that internally they use 'malloc', actually.
Well that explains why I'm still getting the same error using "new"
and "delete".
Make sure you do the right 'delete' -- "delete[]" for arrays.
If 'malloc' somehow overrides (steps onto) some memore you're still
using for some other object, it could be only two things: the heap
is corrupt (your program writes beyond the bounds of a dynamically
allocated object, thus crossing over to memory that doesn't really
belong to it, OR your "part of previously defined class" was somehow
transferred from under your control and it's now part of the heap
that 'malloc' is free to reuse.
The old code is horrendous, with objects being used before they
exist, and other inappropriate actions. I'm really not surprised
that this is happening, just confused about how to solve it with no
*apparent* errors. I was hoping that this was going to be more of an
oversight on my part than anything. The object that is being
overwritten is most likely being re-initialized somewhere. If I
re-allocate an object doing:
gsPpk = new ObjectDef();
then later in the code do
gsPpk = new ObjectDef();
again, what happens?
Nothing awful, most likely.
Is the original instance of the object lost and
that memory locked?
The original instance is "lost" in terms of gaining access to it, but
the memory is still allocated. This is what's known to be "a memory
leak", since the memory is (and cannot be) deallocated because the
pointer to that memory has been lost when you override the value in
the 'gsPpk'. Unless, of course, somebody holds onto the value of the
pointer, which in itself may be a BAD IDEA(tm).
[..]
Memory access troubles are the worst, and if you get them under your
control, you're going to be very happy.
c:\stupidproject>del /f /s *.*
would make me happy.
I hear you.
Besides my typos, everything looks fine? Thanks for your advice,
that's what I needed to know. I am still relatively new to the C++
environment, being an old Delphi programmer, so outside perspective
is always appreciated.
Here is something you might want to consider: do NOT use dynamic
memory allocated directly by you, instead use standard containers.
Switch to using 'std::vector<float>' instead of 'malloc'ed 'float*'.
Easier to debug, for sure.
If only it were that simple. If I could merely do a gloabl
search/replace, my life would be so much simpler.
Refactoring old C code is not much fun. But it's often what you have
to do and it's better done right. That includes stopping the use of
"naked" pointers for arrays and switching to using proper standard
containers. While it looks daunting at first, you will save more time
later if you have done that.
Talk you your boss, ask for an extension of couple of days, back your
project up in a reliable location, then comb those "naked" pointers
out and replace them with vectors. You'll be glad you do.
V
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