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46 lines
2.1 KiB
Markdown
46 lines
2.1 KiB
Markdown
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The [_MEMGET](_MEMGET) function returns a value from a specific memory block name at the specified OFFSET using a certain variable type.
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## Syntax
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> returnValue = [_MEMGET](_MEMGET)(memoryBlock, bytePosition, variableType)
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## Parameter(s)
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* Returns a value of the variableType designated. The holding variable must match that [TYPE](TYPE).
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* memoryBlock is a [_MEM](_MEM) variable type memory block name created by [_MEMNEW](_MEMNEW) or the [_MEM (function)](_MEM-(function)) function.
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* bytePosition is the memoryBlock.[OFFSET](OFFSET) memory start position plus any bytes to move into the block.
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* variableType is a variable [TYPE](TYPE) like [_BYTE](_BYTE), [INTEGER](INTEGER), [SINGLE](SINGLE), [DOUBLE](DOUBLE), etc.
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## Description
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* memoryBlock.[OFFSET](OFFSET) returns the starting byte position of the block. Add bytes to move into the block.
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* The variable type held in the memory block can determine the next bytePosition to read.
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* [LEN](LEN) can be used to determine the byte size of numerical or user defined variable [Variable Types](Variable-Types)s regardless of the value held.
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* [STRING](STRING) values should be of a defined length. Variable length strings can actually move around in memory and not be found.
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* **_MEMGET variable values that are assigned a variable [Variable Types](Variable-Types) other than a memory type do not need to be freed.**
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## Example(s)
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[DEF SEG](DEF-SEG) and [VARPTR](VARPTR) are no longer necessary to do things in memory just like [POKE](POKE) and [PEEK](PEEK) do.
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```vb
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DIM o AS _MEM
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o = _MEM(d&) 'OLD... o% = VARPTR(d&)
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_MEMPUT o, o.OFFSET + 1, 3 AS _UNSIGNED _BYTE 'a POKE
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v = _MEMGET(o, o.OFFSET + 1, _UNSIGNED _BYTE) 'a PEEK
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PRINT v 'prints 3
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PRINT d& 'prints 768 because the 2nd byte of d& has been set to 3 or 3 * 256
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_MEMFREE o
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```
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> *Explanation:* The memory block and OFFSET are given by [_MEMPUT](_MEMPUT) and the _MEMGET function, with the designated type.
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## See Also
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* [_MEM](_MEM), [MEM (function)](MEM-(function))
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* [_MEMGET](_MEMGET), [_MEMPUT](_MEMPUT)
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* [_MEMNEW](_MEMNEW), [_MEMFILL](_MEMFILL)
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* [_MEMCOPY](_MEMCOPY)
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