Function jemalloc_sys::xallocx

pub unsafe extern "C" fn xallocx(
    ptr: *mut c_void,
    size: size_t,
    extra: size_t,
    flags: c_int
) -> size_t

Resizes the previously-allocated memory region referenced by ptr in place to be at least size bytes, returning the real size of the allocation.

Deallocates the old object pointed to by ptr and sets ptr to a new object that has the size returned; the old a new objects share the same base address. The contents of the new object are the same as that of the old object prior to deallocation, up to the lesser of the new and old sizes.

If extra is non-zero, an attempt is made to resize the allocation to be at least size + extra bytes. Inability to allocate the extra bytes will not by itself result in failure to resize.

The memory in the new object beyond the size of the old object is obtained according to flags (it might be uninitialized).

Errors

If the allocation cannot be adequately grown in place up to size, the size returned is smaller than size.

Note:

• the size value returned can be larger than the size requested during allocation
• when shrinking an allocation, use the size returned to determine whether the allocation was shrunk sufficiently or not.

Safety

The behavior is undefined if:

• size == 0, or
• size + extra > size_t::max_value(), or
• ptr does not match a pointer earlier returned by the memory allocation functions of this crate, or
• the memory region referenced by ptr has been deallocated.