🚀 go-pugleaf

Moises Lejter (mlm@cs.brown.edu) wrote:
:   Jerry>
:   Jerry> On the other hand, UNIX provides very robust virtual memory
:   Jerry> capabilities, so most programs can get by using only the
:   Jerry> unsophisticated heap management of malloc() and related
:   Jerry> functions.
:
: I am not sure how fair this statement is to modern versions of UNIX.
: It is true that the OS itself provides rudimentary facilities for
: expanding the heap - just sbrk() to extend heap memory.  However, the
: standard C library's heap allocation routines (malloc() and friends)
: do try to do a reasonable job in terms or reusing freed blocks,
: compacting contiguous free blocks when convenient.  I will grant you
: it is possible to construct an application whose dynamic memory
: behavior will defeat the strategies in the standard C library, but I
: am not sure that this is commonly a problem...
:

It's not a question of defeating the standard C library; there are some
things that malloc() simply cannot do.  Sure, it can coalesce adjacent
free blocks, but it cannot compact the heap by moving the allocated blocks,
because it has no way of fixing up the pointers into those blocks.

: Moises
--
Jerry J. Shekhel
jerry@cybercom.net