I think these questions about stack unwinding are valuable. If you really do actually want answers, you should probably, in this order, (a) study the actual pr

I think these questions about stack unwinding are valuable. If you really do actually want answers, you should probably, in this order, (a) study the actual proposal in detail and not confuse it with an imperfect reference implementation, (b) check comp.std.c for previous discussions on the topic and maybe ask there, (c) see if there are other previous discussions involving the members who proposed this (maybe the standard committee has some semi-public mailing list or something?) and maybe ask there, (d) contact the email address given in the proposal. In all cases, it's probably a very good idea to stay as civil as you were in this post, not as confrontational as you were above. I'm stressing that you should study the proposal because some of the things you got hung up before were not properties of the proposal but only of the reference implementation. Besides the longjmp issue, the dynamic allocation issue might be in this category as well. The proposal doesn't mention DEFER_ENOMEM, I think a compiler would have enough information in any case to allocate the needed space on the stack.