Detect memory leaks.
Positive value tells the framework to detect the memory leaks (if any). In addition any value greater than 1 is treated as leak allocation number and setups runtime breakpoint. In other words setting this parameter to the positive value N greater than 1 causes the framework to set a breakpoint at Nth memory allocation (don't do that from the command line - only when you are under debugger).
If your test program produces memory leaks notifications, they are combined with allocation number values you could use to set a breakpoint.
Currently only applies to MS family of compilers in debug builds.