_MEMGET (function) - QB64 Wiki

_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.


Contents

Syntax

returnValue = _MEMGET(memoryBlock, bytePosition, variableType)


Parameters

  • Returns a value of the variableType designated. The holding variable must match that TYPE.
  • memoryBlock is a _MEM variable type memory block name created by _MEMNEW or the _MEM function.
  • bytePosition is the memoryBlock.OFFSET memory start position plus any bytes to move into the block.
  • variableType is a variable TYPE like _BYTE, INTEGER, SINGLE, DOUBLE, etc.


Description

  • memoryBlock.OFFSET returns the starting byte position of the block. Add bytes to move into the block.
  • The variable type held in the memory block can determine the next bytePosition to read.
  • LEN can be used to determine the byte size of numerical or user defined variable types regardless of the value held.
  • STRING values should be of a defined length. Variable length strings can actually move around in memory and not be found.
  • _MEMGET variable values that are assigned a variable type other than a memory type do not need to be freed.


Examples

Example: DEF SEG and VARPTR are no longer necessary to do things in memory just like POKE and PEEK do.

DIM o AS _MEM o = _MEM(d&) 'OLD... o% = VARPTR(d&) _MEMPUT o, o.OFFSET + 1, 3 AS _UNSIGNED _BYTE 'a POKE v = _MEMGET(o, o.OFFSET + 1, _UNSIGNED _BYTE) 'a PEEK PRINT v 'prints 3 PRINT d& 'prints 768 because the 2nd byte of d& has been set to 3 or 3 * 256 _MEMFREE o

Explanation: The memory block and OFFSET are given by _MEMPUT and the _MEMGET function, with the designated type.


See also



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