_MEM (function)

From QB64 Phoenix Edition Wiki
Revision as of 12:02, 19 April 2022 by SMcNeill (talk | contribs) (Created page with "{{DISPLAYTITLE:_MEM (function)}} The _MEM function returns a _MEM block referring to the largest possible continuous memory region beginning at a variable's offset. {{PageSyntax}} : {{Parameter|memoryBlock}} = _MEM({{Parameter|referenceVariable}}) ===Unsecure syntax=== : {{Parameter|memoryBlock}} = _MEM({{Parameter|offset}}, {{Parameter|byteSize}}) {{Parameters}} * The {{Parameter|memoryBlock}} created will hold the {{Parameter|referenceVariable}} or a...")
(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Jump to navigation Jump to search

The _MEM function returns a _MEM block referring to the largest possible continuous memory region beginning at a variable's offset.


Syntax

memoryBlock = _MEM(referenceVariable)

Unsecure syntax

memoryBlock = _MEM(offset, byteSize)


Template:Parameters

  • The memoryBlock created will hold the referenceVariable or array value(s), type and byte size in a separate memory area.
  • The secure syntax referenceVariable is an existing variable's referenced memory block.
  • The unsecure syntax's designated offset and byteSize cannot be guaranteed. Avoid if possible.


Description

  • The memoryBlock _MEM type variable holds the following read-only elements: OFFSET, SIZE, TYPE and ELEMENTSIZE.
  • All values created by memory functions MUST be freed using _MEMFREE with a valid _MEM variable type.
  • _MEM function cannot reference variable length STRING variable values. String values must be designated as a fixed-length string.


Examples

Example: Assigning values to reference variables in memory.

  
DIM SHARED m(3) AS _MEM
DIM SHARED Saved(3)

m(1) = _MEM(x)
m(2) = _MEM(y)
m(3) = _MEM(z)

x = 3: y = 5: z = 8
PRINT x, y, z
Save x, y, z
x = 30: y = 50: z = 80
PRINT x, y, z

RestoreIt
PRINT x, y, z

_MEMFREE m(1)
_MEMFREE m(2)
_MEMFREE m(3)
END

SUB Save (n1, n2, n3)
Saved(1) = n1
Saved(2) = n2
Saved(3) = n3
END SUB

SUB RestoreIt
_MEMPUT m(1), m(1).OFFSET, Saved(1)
_MEMPUT m(2), m(2).OFFSET, Saved(2)
_MEMPUT m(3), m(3).OFFSET, Saved(3)
END SUB  
Code by SMcNeill


See also



Navigation:
Main Page with Articles and Tutorials
Keyword Reference - Alphabetical
Keyword Reference - By usage
Report a broken link