# Memory user defined functions Reference

Below is a complete list of the user defined functions available in AutoIt. Click on a user defined function name for a detailed description.

When using them you need to add a #include <Memory.au3>.

User Defined Function | Description
--- | ---
_MemGlobalAlloc | Allocates the specified number of bytes from the heap
_MemGlobalFree | Frees the specified global memory object and invalidates its handle
_MemGlobalLock | Locks a global memory object and returns a pointer to the first byte of the object's memory block
_MemGlobalReAlloc | ReAllocates the specified number of bytes from the heap
_MemGlobalSize | Retrieves the current size of the specified global memory object
_MemGlobalUnlock | Decrements the lock count associated with a memory object that was allocated with GMEM_MOVEABLE
_MemMoveMemory | Moves memory either forward or backward, aligned or unaligned
_MemVirtualAlloc | Reserves or commits a region of pages in the virtual address space of the calling process
_MemVirtualAllocEx | Reserves a region of memory within the virtual address space of a specified process
_MemVirtualFree | Releases a region of pages within the virtual address space of a process
_MemVirtualFreeEx | Releases a region of pages within the virtual address space of a process