mem

max

M Functions

member

 

AutoLISP Reference Guide > AutoLISP Functions > M Functions > 

mem

Displays the current state of the AutoLISP memory

(mem)

The mem function displays statistics on AutoLISP memory usage. The first line of this statistics report contains the following information:

GC calls

Number of garbage collection calls since AutoLISP started.

GC run time

Total time spent collecting garbage (in milliseconds).

LISP objects are allocated in dynamic (heap) memory that is organized in segments and divided into pages. Memory is described under the heading, “Dynamic Memory Segments Statistics”:

PgSz

Dynamic memory page size (in KB).

Used

Number of pages used.

Free

Number of free (empty) pages.

FMCL

Largest contiguous area of free pages.

Segs

Number of segments allocated.

Type

Internal description of the types of objects allocated in this segment. These include

lisp stacks—LISP internal stacks

bytecode area—compiled code function modules

CONS memory—CONS objects

::new—untyped memory requests served using this segment

DM Str—dynamic string bodies

DMxx memory—all other LISP nodes

bstack body—internal structure used for IO operations

The final line in the report lists the minimal segment size and the number of allocated segments. AutoLISP keeps a list of no more than three free segments in order to save system calls for memory requests.

All heap memory is global; that is, all AutoCAD documents share the same heap. This could change in future releases of AutoCAD.

Note that mem does not list all memory requested from the operating system; it lists only those requests served by the AutoLISP Dynamic Memory (DM) subsystem. Some AutoLISP classes do not use DM for memory allocation.

Return Values

nil

Examples

Command: (mem)

; GC calls: 23; GC run time: 298 ms

Dynamic memory segments statistic:

PgSz  Used  Free  FMCL  Segs  Type

 512    79    48    48     1  lisp stacks

 256  3706   423   142    16  bytecode area

4096   320    10    10    22  CONS memory

  32   769  1213  1089     1  ::new

4096   168    12    10    12  DM Str

4096   222     4     4    15  DMxx memory

 128     4   507   507     1  bstack body

Segment size: 65536, total used: 68, free: 0

nil