Recently I tried to learn templates and I wanted to put them to use writing a very simple memory manager (wrappers on new and delete, actually). I met a strange behaviour of STL string I cannot explain logically.
Consider these two pieces of code:
#include <iostream>
#include <string>
class MemoryManager
{
public:
MemoryManager(){}
~MemoryManager(){}
template <class allocType> void allocate(allocType* _data, unsigned int _size, std::string _source)
{
_data = new allocType[_size];
};
};
MemoryManager memman;
int main()
{
float* i;
memman.allocate<float>(i,1,"test");
*i = 5; // crash here
std::cout << *i;
return 0;
};
and a second one, with different function arguments
#include <iostream>
#include <string>
class MemoryManager
{
public:
MemoryManager(){}
~MemoryManager(){}
template <class allocType> void allocate(allocType* _data, unsigned int _size)
{
_data = new allocType[_size];
};
};
MemoryManager memman;
int main()
{
float* i;
memman.allocate<float>(i,1);
*i = 5;
std::cout << *i;
return 0;
};
Now, the second code works flawlessly. On the other hand, the first one crashes in debug mode and works fine in release. Does anyone have an idea what's going on? I don't even USE the passed string, it must be STL doing something to me :(
By the way, I am using Code::Blocks and MinGW.
