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45 lines
2.3 KiB
Text
45 lines
2.3 KiB
Text
{{DISPLAYTITLE:_MEMGET (function)}}
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The [[_MEMGET]] function returns a value from a specific memory block name at the specified OFFSET using a certain variable type.
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{{PageSyntax}}
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: {{Parameter|returnValue}} = [[_MEMGET]]({{Parameter|memoryBlock}}, {{Parameter|bytePosition}}, {{Parameter|variableType}})
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{{PageParameters}}
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* Returns a value of the {{Parameter|variableType}} designated. The holding variable must match that [[TYPE]].
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* {{Parameter|memoryBlock}} is a [[_MEM]] variable type memory block name created by [[_MEMNEW]] or the [[_MEM (function)|_MEM]] function.
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* {{Parameter|bytePosition}} is the {{Parameter|memoryBlock}}.[[OFFSET]] memory start position plus any bytes to move into the block.
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* {{Parameter|variableType}} is a variable [[TYPE]] like [[_BYTE]], [[INTEGER]], [[SINGLE]], [[DOUBLE]], etc.
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{{PageDescription}}
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* {{Parameter|memoryBlock}}.[[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 {{Parameter|bytePosition}} to read.
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* [[LEN]] can be used to determine the byte size of numerical or user defined variable [[Variable Types|type]]s regardless of the value held.
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* [[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|type]] other than a memory type do not need to be freed.'''
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{{PageExamples}}
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''Example:'' [[DEF SEG]] and [[VARPTR]] are no longer necessary to do things in memory just like [[POKE]] and [[PEEK]] do.
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{{CodeStart}} '' ''
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{{Cl|DIM}} o {{Cl|AS}} {{Cl|_MEM}}
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o = {{Cl|_MEM (function)|_MEM}}(d&) 'OLD... o% = VARPTR(d&)
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{{Cl|_MEMPUT}} o, o.OFFSET + 1, 3 {{Cl|AS}} {{Cl|_UNSIGNED}} {{Cl|_BYTE}} 'a POKE
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v = {{Cl|_MEMGET (function)|_MEMGET}}(o, o.OFFSET + 1, {{Cl|_UNSIGNED}} {{Cl|_BYTE}}) 'a PEEK
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{{Cl|PRINT}} v 'prints 3
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{{Cl|PRINT}} d& 'prints 768 because the 2nd byte of d& has been set to 3 or 3 * 256
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{{Cl|_MEMFREE}} o
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{{CodeEnd}}
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:''Explanation:'' The memory block and OFFSET are given by [[_MEMPUT]] and the _MEMGET function, with the designated type.
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{{PageSeeAlso}}
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* [[_MEM]], [[MEM (function)]]
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* [[_MEMGET]], [[_MEMPUT]]
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* [[_MEMNEW]], [[_MEMFILL]]
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* [[_MEMCOPY]]
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{{PageNavigation}}
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