Is there any way to prevent std::function in gcc from dynamically allocating memory for larger function objects?
I would have expected the following code to work without dynamic allocation:
#include <functional>
#include <iostream>
// replace operator new and delete to log allocations
void* operator new (std::size_t n) {
std::cout << "Allocating " << n << " bytes" << std::endl;
return malloc(n);
}
void operator delete(void* p) throw() {
free(p);
}
class TestPlate
{
private:
int value;
public:
int getValue(){ return value; }
void setValue(int newValue) { value = newValue; }
int doStuff(const std::function<int()>& stuff) { return stuff(); }
};
int main()
{
TestPlate testor;
testor.setValue(15);
const std::function<int()>& func = std::bind(&TestPlate::getValue, &testor);
std::cout << testor.doStuff(func) << std::endl;
testor.setValue(25);
std::cout << testor.doStuff(func) << std::endl;
}
However it allocates 24 bytes. As far as I am able to tell this is because the pointer to method requires 16 bytes and the pointer to the class instance another 8 bytes. This seems to be either A larger than the internal memory available to the function object or B a plain bug.
I was wondering whethere there are is any way to circumvent this type of behavior without changing the signature of the std::function or creating a lot of additional wrapper code.
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