Because (m)alloc predates mmap by a decade or so [1], and you expressly don't want stack-like allocation semantics when using malloc (otherwise you'd just put i

Because (m)alloc predates mmap by a decade or so [1], and you expressly don't want stack-like allocation semantics when using malloc (otherwise you'd just put it on a/the stack). [1] And you cannot have more than one heap without mmap. Without mmap, you only have sbrk = the one heap. On UNIX and those that pretend to be, anyway.