Re: overriding placement new + memory management
On May 4, 10:23 am, "Lagarde S=E9bastien" <slaga...@e-neko.com> wrote:
I write code to debug new call with following macro:
#define new (MemoryManager::Get().setOwner (__FILE__, __LINE__, _FUNCTION=
-),
FALSE) ? NULL : new
[...]
The problem is with placement new, : I don't want to debug
placement new, this is not required, but as my macro is there
I enter in SetOwner, so in the critical section but never
leave...
So to resolve the problem I wrote my own version of placement new:
inline void* __cdecl operator new[](size_t, void* anywhere)
{
leaveCriticalSection();
return anywhere;
}
but my version of placement news seems to never been call and I block in
critical section.
If operator new is inline, then the original version has already
been compiled into the library code.
Formally, using #define to define a keyword is undefined
behavior if you include any standard header. Practically, I
wouldn't be a bit surprised if it didn't cause problems if you
do it before including the standard headers: all it takes is for
a template to be used in two different translation units.
The usual solution here is to write system specific code to do a
stack walkback in the debugging operator new. This only gives
you a hex dump of the stack, to begin with, but it's not as if
you need to use the information that often, and usually, there
are platform specific tools available which will interpret the
hex addresses for you. The stack walkback code is, of course,
very, very platform specific, but it's rather straightforward on
Intel architecture, and g++ has an extention in its runtime that
you can use with it, so those two platforms are easy.
I read on a web page that replacing global placement new is
illegal. Is it true ?
I think so. It's not listed among the functions you can
replace. (Note too that the replacement functions are NOT
allowed to be inline. This is to ensure that even library code
compiled elsewhere will get the replacement.)
--
James Kanze (GABI Software) email:james.kanze@gmail.com
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