Comment by scott_s

Because sometimes the tasks you need to perform cascade, and then you're repeating that cascade all over the place. As I pointed out upthread, check out the Linux kernel: http://lxr.free-electrons.com/source/kernel/fork.c?v=3.3#L42...

Notice the cascade after the 'out' label; each label after it is for a different level of cleanup needed, depending on how deep into the system call the function encountered the error. Also notice that this is basically the kind of code one would generate for exceptions.