_MEMGET - QB64 Wiki

_MEMGET

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The _MEMGET statement reads a portion of a memory block at an OFFSET position into a variable, array or user defined type.


Syntax:

_MEMGET memory_block, byte_position, holding_variable


  • memory block is a _MEM variable type memory block name created by _MEMNEW or the _MEM function.
  • mandatory byte_position is the memory_block.OFFSET memory start position plus any bytes to move into the block.
  • holding variable is the variable assigned to hold the data. The number of bytes read is determined by the variable type used.


Usage:

  • The _MEMGET statement is similar to the GET statement used in files, but the position is required.
  • The memory block name.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 byte position to read.
  • LEN(variable) can determine the byte size of numerical or user defined variable types irregardless 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.


Example: Shows how to read the PSET color values from a program's SCREEN memory to an array.

SCREEN 13 PSET (0, 0), 123 PSET (1, 0), 222 'create screen image 'here is an array DIM screen_array(319, 199) AS _UNSIGNED _BYTE 'use screen dimensions from 0 'here's how we can copy the screen to our array DIM m AS _MEM m = _MEMIMAGE '0 or no handle necessary when accessing the current program screen _MEMGET m, m.OFFSET, screen_array() 'here's the proof PRINT screen_array(0, 0) 'print 123 PRINT screen_array(1, 0) 'print 222 END


See also:



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