Fix UB in heap init example docs

riscv-rt/CHANGELOG.md

@@ -21,6 +21,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ### Fixed
 
+- Fix undefined behavior in heap initialization example documentation
 - Fix stack allocation algorithm for multi-core targets without M extension
 
 ## [v0.16.0] - 2025-09-08

riscv-rt/src/lib.rs

@@ -279,7 +279,7 @@
 //! fn main() {
 //!     unsafe {
 //!         let heap_bottom = riscv_rt::heap_start() as usize;
-//!         let heap_size = &_heap_size as *const u8 as usize;
+//!         let heap_size = core::ptr::addr_of!(_heap_size) as usize;
 //!         some_allocator::initialize(heap_bottom, heap_size);
 //!     }
 //! }