Public Methods
Let us take a look at the public methods provided in this class.
CComAllocator::Allocate
Allocate is a static function used to allocate memory to a COM object. It takes the number of bytes to be allocated as the parameter.
Syntax:
static void* Allocate(size_t nBytes) throw();
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This method returns a void pointer to the allocated space. It may also return NULL if the memory available is not sufficient.
CComAllocator::Free
This method is also a static function. It is used to free the allocated memory. It takes the pointer pointing to the allocated memory as the parameter.
Syntax:
static void Free(void* p) throw();
Here, ‘p’ is the pointer to the allocated memory.
CComAllocator::Reallocate
This static function is used to reallocate memory. It is useful when we change the size of an already existing object. It takes the pointer pointing to the allocated memory and byte size as parameters.
Syntax:
static void* Reallocate(void* p, size_t nBytes) throw();
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Here, ‘p’ is the pointer to the allocated memory and ‘nBytes’ is the number of bytes to reallocate.
This function returns a void pointer to the allocated space. It may also return NULL if the memory present is insufficient.
Frequently Asked Questions
What is the use of the throw() keyword?
The throw() keyword is used to specify whether a function does not throw any exceptions regardless of whether it contains try/catch blocks. This can be useful for improving the performance of the function, as the compiler can optimize the code, knowing that it does not need to generate any exception-handling code.
What do you understand by COM?
COM (Component Object Model) is a platform-independent, object-oriented system for creating binary software applications that can interact. COM defines a set of rules and conventions for creating and using binary software components that are flexible, modular, and easy to develop.
What is the difference between static and dynamic functions?
A static function is a function with a single copy in memory that is shared by all class instances. This means that the function is not bound to any particular class instance and can be called using the class name rather than an object of the class. On the other hand, a dynamic function is a function bound to a specific class instance and can only be called using an object of the class.
Conclusion
This blog discussed the CComAllocator Class. We learned about its various methods and their syntax. We say how to assign and free memory of COM objects.
If you wish to learn more about ATL, you can refer to the following blogs.
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