Function nstd_alloc_reallocate 

#[unsafe(no_mangle)]
pub unsafe extern "C" fn nstd_alloc_reallocate(
    ptr: &mut NSTDAnyMut,
    old_layout: NSTDAllocLayout,
    new_layout: NSTDAllocLayout,
) -> NSTDAllocError

Available on crate feature alloc only.

Reallocates memory that was previously allocated by this allocator.

On successful reallocation, ptr will point to the new memory location and NSTD_ALLOC_ERROR_NONE will be returned. If this is not the case and reallocation fails, the pointer will remain untouched and the appropriate error is returned.

Parameters:

• NSTDAnyMut *ptr - A pointer to the allocated memory.

• NSTDAllocLayout old_layout - Describes the previous memory layout.

• NSTDAllocLayout new_layout - Describes the new memory layout to allocate for.

Returns

NSTDAllocError errc - The allocation operation error code.

Safety

• Behavior is undefined if new_layout’s size is zero.

• Behavior is undefined if ptr is not a pointer to memory allocated by this allocator.

• old_layout must be the same value that was used to allocate the memory buffer.

Example

use nstd_sys::{
    alloc::{nstd_alloc_allocate_zeroed, nstd_alloc_deallocate, nstd_alloc_reallocate},
    core::alloc::{nstd_core_alloc_layout_new, NSTDAllocError::NSTD_ALLOC_ERROR_NONE},
};


unsafe {
    let mut size = core::mem::size_of::<[u64; 64]>();
    let mut align = core::mem::align_of::<[u64; 64]>();
    let layout = nstd_core_alloc_layout_new(size, align).unwrap();
    let mut mem = nstd_alloc_allocate_zeroed(layout);
    assert!(!mem.is_null());
    assert!(*mem.cast::<[u64; 64]>() == [0u64; 64]);

    size = core::mem::size_of::<[u64; 32]>();
    align = core::mem::align_of::<[u64; 32]>();
    let new_layout = nstd_core_alloc_layout_new(size, align).unwrap();
    assert!(nstd_alloc_reallocate(&mut mem, layout, new_layout) == NSTD_ALLOC_ERROR_NONE);
    assert!(*mem.cast::<[u64; 32]>() == [0u64; 32]);

    assert!(nstd_alloc_deallocate(mem, new_layout) == NSTD_ALLOC_ERROR_NONE);
}