Associates a custom name with a memory range.
Registering a block allows Memcheck to report errors (invalid accesses,
uninitialized reads) using a specific description string rather than the generic
allocation stack trace.
This modifies error reporting context only; it does not change the
accessibility, definedness, or any other physical properties of the memory.
# Arguments
- `addr` - The starting address of the memory range.
- `size` - The length of the range in bytes.
- `desc` - A null-terminated C string describing the block.
## Note
Requires Valgrind **3.2** or higher.