When your program allocates a memory block, any data written outside of the block results in data corruption.

To quickly identify instances in which your program may be incorrectly writing data either before or after a block, use guard blocks. Guard blocks are small blocks of additional memory created just before and after an allocated block. At initialization, TotalView writes a bit pattern into these guard blocks so you can quickly see if they are overwritten or corrupted via a memory event report or event notification.