_MEMGET - QB64Official/qb64 GitHub Wiki

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

Syntax

_MEMGET memoryBlock, bytePosition, destinationVariable

  • memoryBlock is a _MEM variable type memory block name created by _MEMNEW or the _MEM (function) function.
  • bytePosition is the memoryBlock.OFFSET memory start position plus any bytes to move into the block.
  • destinationVariable is the variable assigned to hold the data. The number of bytes read is determined by the variable Variable Types used.

Description

  • 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 bytePosition to read.
  • LEN can be used to determine the byte size of numerical or user defined variable Variable Typess 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.

Example(s)

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