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Description
Reallocate a block of memory previously allocated by Heap_Alloc, while preserving the original content.
Old memory block is released.
Syntax
ptr = HEAP_ReAlloc(OldPtr, Size)
Returns
DWORD
value > 0, if the function succeeds. Pointer to the new allocated memory block.
value = 0 in case of error.
Parameters
Name |
Type |
Optional |
Meaning |
OldPtr |
Number |
No |
Pointer to memory previously allocated by Heap_Alloc. If zero, a completely new block of memory will be allocated. |
Size |
Number |
No |
Number of bytes to allocate. Up to 2GB. |
Remarks
The theoretical maximum of 2 147 483 647 bytes is mostly theoretical, as 32bit process cannot address more than 2GB of RAM and thinBASIC process already occupies some memory. The actual number might be also lower due to memory fragmentation.
Restrictions
Use this function only with memory previously allocated by Heap_Alloc.
See also
Heap_Alloc, Heap_ReallocByStr, Redim Preserve
Examples
' Allocate 8 bytes
dim pMemory as dword = heap_alloc(8)
' Overlay array of bytes
dim bytes(8) as byte at pMemory
msgbox 0, "After creation:" + $CRLF + ToHumanReadableByteValues(pMemory)
' Writing data to the allocated memory, via overlay array
bytes(1) = 1, 2, 3, 4, 5, 6, 7, 8
msgbox 0, "After writing to memory via array:" + $CRLF + ToHumanReadableByteValues(pMemory)
' Re-allocate the original 8 bytes to 16 bytes block
dim pNewMemory as dword = heap_reAlloc(pMemory, 16)
msgbox 0, "After memory extension:" + $CRLF + ToHumanReadableByteValues(pNewMemory) + $CRLF(2) + "Notice the preserved original data"
' Release the memory (please note no need to free the original pMemory location)
heap_free(pNewMemory)
function ToHumanReadableByteValues(pMemoryLocation as dword) as string
dim bytes(heap_size(pMemoryLocation)) as byte at pMemoryLocation
return join$(bytes, " ")
end function
