Function tikv_jemalloc_sys::malloc_usable_size
source · pub unsafe extern "C" fn malloc_usable_size(
ptr: *const c_void,
) -> size_t
Expand description
Returns the real size of the previously-allocated memory region
referenced by ptr
.
The value may be larger than the size requested on allocation.
Although the excess bytes can be overwritten by the application without ill effects, this is not good programming practice: the number of excess bytes in an allocation depends on the underlying implementation.
The main use of this function is for debugging and introspection.
§Errors
If ptr
is null, 0 is returned.
§Safety
The behavior is undefined if:
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.