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