What is a Memory Heap

Question

What is a memory heap

User · Accepted Answer

Presumably you mean heap from a memory allocation point of view  not from a data structure point of view  the term has multiple meanings    A very simple explanation is that the heap is the portion of memory where dynamically allocated memory resides  i e  memory allocated via malloc    Memory allocated from the heap will remain allocated until one of the following occurs    The memory is free d The program terminates   If all references to allocated memory are lost  e g  you don t store a pointer to it anymore   you have what is called a memory leak   This is where the memory has still been allocated  but you have no easy way of accessing it anymore   Leaked memory cannot be reclaimed for future memory allocations  but when the program ends the memory will be free d up by the operating system   Contrast this with stack memory which is where local variables  those defined within a method  live   Memory allocated on the stack generally only lives until the function returns  there are some exceptions to this  e g  static local variables    You can find more information about the heap in this article

User · Answer

A memory heap is a common structure for holding dynamically allocated memory  See Dynamic memory allocation on wikipedia    There are other structures  like pools  stacks and piles

User · Answer

You probably mean heap memory  not memory heap   Heap memory is essentially a large pool of memory  typically per process  from which the running program can request chunks  This is typically called dynamic allocation   It is different from the Stack  where  automatic variables  are allocated  So  for example  when you define in a C function a pointer variable  enough space to hold a memory address is allocated on the stack  However  you will often need to dynamically allocate space  With malloc  on the heap and then provide the address where this memory chunk starts to the pointer

User · Answer

It s a chunk of memory allocated from the operating system by the memory manager in use by a process  Calls to malloc   et alia then take memory from this heap instead of having to deal with the operating system directly

User · Answer

A memory heap is a location in memory where memory may be allocated at random access   Unlike the stack where memory is allocated and released in a very defined order  individual data elements allocated on the heap are typically released in ways which is asynchronous from one another   Any such data element is freed when the program explicitly releases the corresponding pointer  and this may result in a fragmented heap   In opposition only data at the top  or the bottom  depending on the way the stack works  may be released  resulting in data element being freed in the reverse order they were allocated

User · Answer

Heap is just an area where memory is allocated or deallocated without any order  This happens when one creates an object using the new operator or something similar  This is opposed to stack where memory is deallocated on the first in last out basis

[malloc] What is a Memory Heap?

Examples related to malloc