How many heaps can be used in a single application and what is their role?

In a typical iOS application, a single main heap is used for dynamic memory allocation. The heap is a region of memory where objects created during program execution are stored, and their size and lifetime are not known in advance.

The role of the heap is to provide flexible memory management for objects that do not fit on the stack or have a long lifespan. In iOS and Swift, memory management is implemented through ARC (Automatic Reference Counting), which automatically tracks the number of references to objects on the heap and frees memory when an object is no longer in use.

Therefore, although technically there can be multiple heaps (for example, in multithreaded environments or when using special allocators), a typical application has just one main heap managed by the system and ARC.