Realloc

Resizes a previously allocated block, preserving its contents.

Module: Std::Memory

Signature

func Realloc(ptr: *opaque, size: uint) -> *opaque;

Parameters

Name	Type	Description
ptr	*opaque	Pointer from a previous Alloc/Realloc, or null.
size	uint	New size of the block, in bytes.

Returns

*opaque — a pointer to the resized block, which may differ from ptr if the block was moved. Returns null if the allocation fails, or if size is 0.

Description

Realloc changes the size of the block pointed to by ptr:

• If ptr is null, it behaves like Alloc(size).
• If size is 0, the block is released with Free and null is returned.
• Otherwise the existing contents are preserved up to the smaller of the old and new sizes; any newly added bytes are uninitialized.

WARNING

On success the original ptr is invalid — use the returned pointer instead. On failure (null) the original block is left untouched, so keep a copy of ptr until Realloc succeeds to avoid leaking it.

Example

import Std::Memory::*;

var buffer = Alloc(1024);

let grown = Realloc(buffer, 2048);
if grown == null {
    Free(buffer); // original is still valid on failure
    return 1;
}
buffer = grown;

Free(buffer);

See also

• Alloc — allocate a new block
• Free — release an allocation