Hi,
I have been playing around with the suggestions and code shown in
regarding memory allocation/deallocation (mem pools). I think I understand
what the FAQ was getting at (emphasis on "think") so I concluded that
attempting to make a delete statement on an area of memory that was created
in a pool with the placement new operator (overloaded) would not allow me to
call an overloaded delete operator with the signature that included the pool
in the parm list, which was shown in the FAQ example. Am I correct? The
sample code is below. I hard-wired the template selector for this example
after creating a pool_alloc template class in an effort to separate the
different types of memory blocks.
// main.cpp
#include <iostream>
class MemoryPool
{
public:
void *calloc( unsigned size )
{
void *memory = malloc( size );
if( !memory ) { cout << "Out of memory!\n"; return 0; }
memset(memory, 0, size);
return memory;
}
void deallocate( void *block )
{
free( block );
}
};
template <short BLOCK_TYPE = 0>
class pool_alloc
{
public:
inline void * operator new( unsigned s, MemoryPool& p )
{ return p.calloc(s);}
// I want to call this delete
void operator delete( void *mem, MemoryPool& p )
{ if( mem ) p.deallocate( mem );}
};
class Foo : public pool_alloc<1>
{
public:
Foo():fooInt(0) {};
Foo( MemoryPool& p, unsigned len ) {};
~Foo() {};
private:
int fooInt;
};
int main( void )
{
Foo *fooP;
MemoryPool p;
fooP = new(p) Foo( p, 3 );
// with this delete statement
//but don't think it's possible or even makes sense
delete fooP;
}
When I compile this code I get the error I thought I'd get:
error: no suitable `operator delete' for `Foo'
And when I add a delete operator without the MemoryPool reference in the
signature, all is well. That too makes sense to me. I don't think there's
a way to call the delete operator and have it "know about" the pool where
the alloc'd memory resides. Again, am I on the right track here?
Thanks in advance,
Jerry
I have been playing around with the suggestions and code shown in
regarding memory allocation/deallocation (mem pools). I think I understand
what the FAQ was getting at (emphasis on "think") so I concluded that
attempting to make a delete statement on an area of memory that was created
in a pool with the placement new operator (overloaded) would not allow me to
call an overloaded delete operator with the signature that included the pool
in the parm list, which was shown in the FAQ example. Am I correct? The
sample code is below. I hard-wired the template selector for this example
after creating a pool_alloc template class in an effort to separate the
different types of memory blocks.
// main.cpp
#include <iostream>
class MemoryPool
{
public:
void *calloc( unsigned size )
{
void *memory = malloc( size );
if( !memory ) { cout << "Out of memory!\n"; return 0; }
memset(memory, 0, size);
return memory;
}
void deallocate( void *block )
{
free( block );
}
};
template <short BLOCK_TYPE = 0>
class pool_alloc
{
public:
inline void * operator new( unsigned s, MemoryPool& p )
{ return p.calloc(s);}
// I want to call this delete
void operator delete( void *mem, MemoryPool& p )
{ if( mem ) p.deallocate( mem );}
};
class Foo : public pool_alloc<1>
{
public:
Foo():fooInt(0) {};
Foo( MemoryPool& p, unsigned len ) {};
~Foo() {};
private:
int fooInt;
};
int main( void )
{
Foo *fooP;
MemoryPool p;
fooP = new(p) Foo( p, 3 );
// with this delete statement
//but don't think it's possible or even makes sense
delete fooP;
}
When I compile this code I get the error I thought I'd get:
error: no suitable `operator delete' for `Foo'
And when I add a delete operator without the MemoryPool reference in the
signature, all is well. That too makes sense to me. I don't think there's
a way to call the delete operator and have it "know about" the pool where
the alloc'd memory resides. Again, am I on the right track here?
Thanks in advance,
Jerry
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