Chapter 4. Managing the memory heap

The term heap, or memory heap, generally means a free memory pool, from which a process can dynamically allocate chunks of memory. Although the management of the memory heap is the most basic programming task on any operating system environments, the mismanagement of the memory heap is a quite common mistake when developing applications using the C and C++ languages.

AIX provides a useful feature, called malloc debug, to diagnose these misuse of the memory heap without recompiling or modifying application source codes.

The first two sections in this chapter provide basic information about the malloc subsystem on AIX, and the third section explains how to use the malloc debug feature. The last section contains the use of library functions to transparently use process heap or shared memory segments to satisfy memory requests.

• Section 4.1, “Malloc subsystem” on page 166

• Section 4.2, “Memory allocators” on page 169

• Section 4.3, “Use of MALLOCDEBUG options” on page 182

• Section 4.4, “Heap management using MEMDBG” on page 199