mirror of
https://github.com/QB64Official/qb64.git
synced 2024-08-22 11:25:08 +00:00
71 lines
1.7 KiB
Markdown
71 lines
1.7 KiB
Markdown
|
The [_MEM](_MEM) function returns a _MEM block referring to the largest possible continuous memory region beginning at a variable's offset.
|
||
|
|
||
|
## Syntax
|
||
|
|
||
|
> memoryBlock = [_MEM](_MEM)(referenceVariable)
|
||
|
|
||
|
### Unsecure syntax
|
||
|
|
||
|
> memoryBlock = [_MEM](_MEM)(offset, byteSize)
|
||
|
|
||
|
## Parameter(s)
|
||
|
|
||
|
* The memoryBlock created will hold the referenceVariable or [arrays](arrays) value(s), type and byte size in a separate memory area.
|
||
|
* The secure syntax referenceVariable is an existing variable's referenced memory block.
|
||
|
* The unsecure syntax's designated offset and byteSize cannot be guaranteed. **Avoid if possible.**
|
||
|
|
||
|
## Description
|
||
|
|
||
|
* The memoryBlock [_MEM](_MEM) type variable holds the following read-only elements: OFFSET, SIZE, TYPE and ELEMENTSIZE.
|
||
|
* All values created by memory functions MUST be freed using [_MEMFREE](_MEMFREE) with a valid [_MEM](_MEM) variable type.
|
||
|
* **_MEM function cannot reference variable length [STRING](STRING) variable values. String values must be designated as a fixed-[LEN](LEN) string.**
|
||
|
|
||
|
## Example(s)
|
||
|
|
||
|
Assigning values to reference variables in memory.
|
||
|
|
||
|
```vb
|
||
|
|
||
|
DIM SHARED m(3) AS _MEM
|
||
|
DIM SHARED Saved(3)
|
||
|
|
||
|
m(1) = _MEM(x)
|
||
|
m(2) = _MEM(y)
|
||
|
m(3) = _MEM(z)
|
||
|
|
||
|
x = 3: y = 5: z = 8
|
||
|
PRINT x, y, z
|
||
|
Save x, y, z
|
||
|
x = 30: y = 50: z = 80
|
||
|
PRINT x, y, z
|
||
|
|
||
|
RestoreIt
|
||
|
PRINT x, y, z
|
||
|
|
||
|
_MEMFREE m(1)
|
||
|
_MEMFREE m(2)
|
||
|
_MEMFREE m(3)
|
||
|
END
|
||
|
|
||
|
SUB Save (n1, n2, n3)
|
||
|
Saved(1) = n1
|
||
|
Saved(2) = n2
|
||
|
Saved(3) = n3
|
||
|
END SUB
|
||
|
|
||
|
SUB RestoreIt
|
||
|
_MEMPUT m(1), m(1).OFFSET, Saved(1)
|
||
|
_MEMPUT m(2), m(2).OFFSET, Saved(2)
|
||
|
_MEMPUT m(3), m(3).OFFSET, Saved(3)
|
||
|
END SUB
|
||
|
|
||
|
```
|
||
|
|
||
|
## See Also
|
||
|
|
||
|
* [_MEM](_MEM) (variable type)
|
||
|
* [_MEMNEW](_MEMNEW), [_MEMCOPY](_MEMCOPY)
|
||
|
* [_MEMGET](_MEMGET), [_MEMPUT](_MEMPUT)
|
||
|
* [_MEMFILL](_MEMFILL), [_MEMIMAGE](_MEMIMAGE)
|
||
|
* [_MEMFREE](_MEMFREE)
|