Re: overloading new/delete operator
No you haven't. You've replaced the global new and delete
operators. But with something that isn't legal, giving
undefined behavior.
<code>
inline void* operator new(size_t size) throw() {
return TC::MemoryPoolManager::getInstance().allocateMemory(size);
}
inline void operator delete(void* deletable, size_t size) throw() {
TC::MemoryPoolManager::getInstance().releaseMemory(deletable,
size);
}
inline void* operator new [](size_t size) throw() {
return TC::MemoryPoolManager::getInstance().allocateMemory(size);
}
inline void operator delete[](void * deletable, size_t size) throw() {
TC::MemoryPoolManager::getInstance().releaseMemory(deletable,
size);
}
</code>
The global new and delete operators (at least the standard
forms) are not allowed to be defined inline.
Ok, let's assume that there was no keyword inline and my definitions
of
new/delete operators are placed in source file -> it still does not
work.
I use Visual Studio 2005, and for new it works correctly, but when it
comes
to call delete some external delete is called (provided by MS).
Previously I had a problem with static library with global definition
of new/delete
and now I have problem with this (this is called when i use delete in
my code):
C:\ <microsoft visual studio dir>\VC\crt\src\delete2.cpp
/***
*delete2.cpp - defines C++ vector delete routine
*
* Copyright (c) Microsoft Corporation. All rights reserved.
*
*Purpose:
* Defines C++ delete routine.
*
***************************************************************************=
****/
#include <cruntime.h>
#include <malloc.h>
#include <new.h>
#include <windows.h>
#include <rtcsup.h>
void operator delete[]( void * p )
{
RTCCALLBACK(_RTC_Free_hook, (p, 0))
operator delete(p);
}
new operator is called without any problems, eg.:
Code Block 2
<code>
template<typename T>
T*** NMap<T>::alloc3DArray(int c, int sx, int sy) {
T*** data = new T**[c];
mem_begin_ = new T[c*sx*sy];
T* tmp;
for (int i = 0; i < c; i++) {
tmp = (mem_begin_ + i*sx*sy);
data[i] = new T*[sy];
for (int y = 0; y < sy; y++) {
data[i][y] = (tmp + y*sx);
}
}
allocated++;
return data;
}
</code>
but the delete operator is called from somewhere else (it is not
called the one that is defined by me [Code block 1]):
Code Block
<code>
template<typename T>
void NMap<T>::free3DArray(T*** data, int c) {
for (int i = 0; i < c; i++) {
T** d = data[i]; //some external delete
delete[] d;
}
delete[] data;
delete[] mem_begin_;
deallocated++;
}
</code>
where is the problem ???
Well, first, you have undefined behavior, because you've defined
your replacement new and delete operators inline. Then, you go
out of your way to ensure that the undefined behavior will cause
problems, by using templates, so you don't know where what will
be allocated or deleted.
The question is what you really want to do:
-- If you really want to replace the global new and delete, it
should be sufficient to put your functions in a source file,
compile it, and link it in before the standard C++ library.
(The standard doesn't say this---it doesn't say anything
about *how* you compile and link. But this works for all
compilers I've ever seen: Sun CC, g++, xlC, VC++...).
Generally, however, this is a bad idea, except for global
debugging versions of the operators.
Yes, I want to replace global new and delete.
How can I do this in Visual C++ 2005 Express Edition?
How can I link the code before the standard C++ library ?
Best Regards
/jerzy stachera
--
James Kanze (GABI Software) email:james.ka...@gmail.com
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