Copyright Digital Equipment Corp. All rights reserved.
Arguments
zone-id
OpenVMS usage:identifier
type: quadword (unsigned)
access: write only
mechanism: by reference
Zone identifier. The zone-id argument is the address of a
quadword that is set to the zone identifier of the newly created
zone.
algorithm
OpenVMS usage:quadword_signed
type: quadword integer (signed)
access: read only
mechanism: by reference
Algorithm. The algorithm argument is the address of a quadword
integer that represents the code for one of the LIB$VM
algorithms. Use one of the following predefined symbols to
specify this value:
Symbol Value Algorithm
LIB$K_VM_FIRST_FIT 1 First fit
LIB$K_VM_QUICK_FIT 2 Quick fit, lookaside list
LIB$K_VM_FREQ_SIZES 3 Frequent sizes, lookaside list
LIB$K_VM_FIXED 4 Fixed-size blocks
If algorithm is not specified, a default of 1 (first fit) is
used.
algorithm-argument
OpenVMS usage:quadword_signed
type: quadword integer (signed)
access: read only
mechanism: by reference
Algorithm argument. The algorithm-argument argument is the
address of a quadword integer that contains a value specific
to the particular allocation algorithm.
Algorithm Value
First fit Not used, may be omitted.
Quick fit The number of lookaside lists used. The number of
lists must be between 1 and 128.
Frequent The number of lookaside lists used. The number of
sizes lists must be between 1 and 16.
Fixed size The fixed request size (in bytes) for each get
blocks or free request. The request size must be greater
than 0.
The algorithm-argument argument must be specified if you are
using the quick-fit, frequent-sizes or fixed-size-blocks
algorithms. However, this argument is optional, but ignored,
if you are using the first-fit algorithm.
flags
OpenVMS usage:mask_quadword
type: quadword (unsigned)
access: read only
mechanism: by reference
Flags. The flags argument is the address of a quadword integer
that contains flag bits that control various options, as follows:
Bit Value Description
0 LIB$M_VM_BOUNDARY_ Boundary tags for faster freeing.
TAGS
Adds a minimum of 16 bytes to each
block.
1 LIB$M_VM_GET_FILL0 LIB$GET_VM_64; fill with bytes of 0.
2 LIB$M_VM_GET_FILL1 LIB$GET_VM_64; fill with bytes of FF
(hexadecimal).
3 LIB$M_VM_FREE_FILL0 LIB$FREE_VM_64; fill with bytes of 0.
4 LIB$M_VM_FREE_FILL1 LIB$FREE_VM_64; fill with bytes of FF
(hexadecimal).
5 LIB$M_VM_EXTEND_ Adds extents to existing areas if
AREA possible.
6 LIB$M_VM_NO_EXTEND Prevents zone from being extended
beyond its initial size. If you
specify this flag, you must also
specify an initial-size. Extend-size
is not used.
7 LIB$M_VM_TAIL_LARGE Adds areas larger than extend-size
areas to the end of the area list.
Allocations that are larger than
extend-size can result in new areas.
These areas are added to the end of
the area list. (This provides better
memory re-use when allocating small
and very large blocks from the same
zone.)
Bits 8 through 63 are reserved and must be 0.
This is an optional argument. If flags is omitted, the default of
0 (no fill and no boundary tags) is used.
extend-size
OpenVMS usage:quadword_signed
type: quadword integer (signed)
access: read only
mechanism: by reference
Zone extend size. The extend-size argument is the address of
a quadword integer that contains the number of Alpha and I64
pagelets to be added to the zone each time it is extended.
The value of extend-size must be greater than or equal to 1.
This is an optional argument. If extend-size is not specified, a
default of 16 Alpha or I64 pagelets is used.
NOTE
The extend-size argument does not limit the number of blocks
that can be allocated from the zone. The actual extension
size is the greater of extend-size and the number of Alpha
or I64 pagelets needed to satisfy the LIB$GET_VM_64 call
that caused the extension.
initial-size
OpenVMS usage:quadword_signed
type: quadword integer (signed)
access: read only
mechanism: by reference
Initial size for the zone. The initial-size argument is the
address of a quadword integer that contains the number of Alpha
or I64 pagelets to be allocated for the zone as the zone is
created.
This is an optional argument. If you specify a value for initial-
size, the value must be greater than or equal to 0; otherwise,
LIB$_INVARG is returned. If initial-size is not specified or is
specified as 0, no Alpha pagelets or I64 are allocated when the
zone is created. The first call to LIB$GET_VM_64 for the zone
allocates extend-size pagelets on Alpha or I64 systems.
block-size
OpenVMS usage:quadword_signed
type: quadword integer (signed)
access: read only
mechanism: by reference
Block size of the zone. The block-size argument is the address of
a quadword integer specifying the allocation quantum (in bytes)
for the zone. All blocks allocated are rounded up to a multiple
of block-size.
The value of block-size must be a power of 2 between 16 and 512.
This is an optional argument. If block-size is not specified, a
default of 16 is used.
alignment
OpenVMS usage:quadword_signed
type: quadword integer (signed)
access: read only
mechanism: by reference
Block alignment. The alignment argument is the address of a
quadword integer that specifies the required address alignment
(in bytes) for each block allocated.
The value of alignment must be a power of 2 between 8 and 512.
This is an optional argument. If alignment is not specified, a
default of 16 (octaword alignment) is used.
page-limit
OpenVMS usage:quadword_signed
type: quadword integer (signed)
access: read only
mechanism: by reference
Maximum page limit. The page-limit argument is the address of a
quadword integer that specifies the maximum number of Alpha or
I64 pagelets that can be allocated for the zone. The value of
page-limit must be greater than or equal to 0. Note that part of
the zone is used for header information.
This is an optional argument. If page-limit is not specified
or is specified as 0, the only limit is the total process
virtual address space limit imposed by OpenVMS. If page-limit
is specified, then initial-size must also be specified.
smallest-block-size
OpenVMS usage:quadword_signed
type: quadword integer (signed)
access: read only
mechanism: by reference
Smallest block size. The smallest-block-size argument is the
address of a quadword integer that specifies the smallest block
size (in bytes) that has a lookaside list for the quick fit
algorithm.
If smallest-block-size is not specified, the default of block-
size is used. That is, lookaside lists are provided for the first
n multiples of block-size.
zone-name
OpenVMS usage:char_string
type: character string
access: read only
mechanism: by descriptor
Name to be associated with the zone being created. The optional
zone-name argument is the address of a descriptor pointing to the
zone name. If zone-name is not specified, the zone will not have
an associated name.
get-page
OpenVMS usage:procedure
type: procedure value
access: read only
mechanism: by value
Routine that allocates memory. The number and type of the
arguments to this routine must match those of the LIB$GET_VM_
PAGE_64 routine. If get-page is not specified or is specified as
0, the LIB$GET_VM_PAGE_64 routine is used to allocate memory.
free-page
OpenVMS usage:procedure
type: procedure value
access: read only
mechanism: by value
Routine that deallocates memory. The number and type of the
arguments to this routine must match those of the LIB$FREE_VM_
PAGE_64 routine. If free-page is not specified or if free-page
is specified as 0, the LIB$FREE_VM_PAGE_64 routine is used to
deallocate memory.