What is GlobalAlloc?

What is GlobalAlloc?

The GlobalAlloc function allocated a selector that could be used to access the amount of memory you requested. You could access the memory in that selector with a “far pointer”. A “far pointer” is a selector combined with a near pointer.

What is VirtualAlloc?

VirtualAlloc is a Windows function used for low-level memory allocation. It lets you reserve regions of virtual address space and commit pages within those regions.

Which allocation method is better for memory Utilisation in Windows?

A partition allocation method is considered better if it avoids internal fragmentation. When it is time to load a process into the main memory and if there is more than one free block of memory of sufficient size then the OS decides which free block to allocate.

What is NtAllocateVirtualMemory?

The NtAllocateVirtualMemory routine reserves, commits, or both, a region of pages within the user-mode virtual address space of a specified process.

How do I use Virtual Alloc?

I typically allocate with VirtualAlloc as follows: void* p = VirtualAlloc(pAllocateAt, nAllocatedSize, MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE); Where nAllocatedSize is the size rounded to the nearest page size. When pAllocateAt is NULL, it works fine, as the function decides the base address.

Does VirtualAlloc have zero memory?

Memory allocated by this function is automatically initialized to zero. To allocate memory in the address space of another process, use the VirtualAllocEx function.

What are the differences between malloc () and VirtualAlloc ()?

VirtualAlloc is the basic memory allocator in Win32 API. The malloc implementation of Visual C++ relies on VirtualAlloc to acquire memory from OS. VirtualAlloc allocates memory in multiples of page size (typically 4K). Typically, you will use malloc (or new and delete in a C++ project).

Which method is the best among file allocation method?

Explanation: The indexed allocation method is the best file allocation method because it removes the problem of contiguous and linked allocation.

What is WriteProcessMemory?

WriteProcessMemory copies the data from the specified buffer in the current process to the address range of the specified process. Any process that has a handle with PROCESS_VM_WRITE and PROCESS_VM_OPERATION access to the process to be written to can call the function.

What is Lpvoid C?

LPVOID data types are defined as being a “pointer to a void object”. This may seem strange to some people, but the ANSI-C standard allows for generic pointers to be defined as “void*” types. This means that LPVOID pointers can be used to point to different types of objects, without creating a compiler error.