Function GC_foreach_heap_section_inner 

pub unsafe extern "C" fn GC_foreach_heap_section_inner(
    fn_: GC_heap_section_proc,
    client_data: *mut c_void,
)

Apply fn to each heap section and each heap block inside. Similar to GC_apply_to_all_blocks(). Assumes the allocator lock is held at least in the reader mode, but no assertion about it by design. Defined only if the library has been compiled without NO_DEBUGGING macro defined.