devel/ElectricFence 2.0.5p0 OpenBSD

Electric Fence is a different kind of malloc() debugger. It uses the virtual memory hardware of your system to detect when software overruns the boundaries of a malloc() buffer. It will also detect any accesses of memory that has been released by free(). Because it uses the VM hardware for detection, Electric Fence stops your program on the first instruction that causes a bounds violation. It's then trivial to use a debugger to display the offending statement.