Copyright (C) 1992 Free Software Foundation, Inc.

Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies.

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Overall Description

This is a heavily modified version of GNU malloc. It uses mmap as the basic mechanism for obtaining memory from the system, rather than sbrk. This gives it several advantages over the more traditional malloc:

• Several different heaps can be used, each of them growing or shinking under control of mmap, with the mmalloc functions using a specific heap on a call by call basis.
• By using mmap, it is easy to create heaps which are intended to be persistent and exist as a filesystem object after the creating process has gone away.
• Because multiple heaps can be managed, data used for a specific purpose can be allocated into its own heap, making it easier to allow applications to "dump" and "restore" initialized malloc-managed memory regions. For example, the "unexec" hack popularized by GNU Emacs could potentially go away.