Alloc

Alloc, short for allocation, is a term used in computing to describe the process of reserving memory or other resources for use by a program. In programming, allocation can be static (determined at compile time) or dynamic (requested at runtime). Static allocation yields storage that exists for the program’s entire lifetime, while dynamic allocation requests blocks from a memory pool or heap as needed.

Dynamic memory allocation is central to many languages. In C, allocation is performed via library functions such as malloc, calloc, and realloc to obtain blocks, and free to release them. These blocks must be managed by the programmer, with attention to alignment and bounds. If allocation fails, the functions return a null pointer. Similar patterns exist in other languages, though some provide automatic memory management (garbage collection or reference counting), reducing the programmer’s direct control.

Allocations are managed by an allocator, a subsystem that provides blocks of suitable size and tracks usage. Different allocators use various strategies (first-fit, best-fit, segregated free lists, buddy systems) and can affect performance and fragmentation. In practice, efficient allocation is important for speed, memory usage, and locality of reference.

A common object-oriented usage is in Objective-C, where the class method [SomeClass alloc] allocates memory for a new instance, which is subsequently initialized with an init method. In managed environments, allocation is often hidden behind higher-level constructs, while low-level code may require meticulous lifecycle handling.