Digest for comp.lang.c++@googlegroups.com - 4 updates in 3 topics

comp.lang.c++@googlegroups.com

Google Groups

Topic digest
View all topics

• xkcd: Y2K and 2038 - 1 Update
• Simulating halt decider applied to a simpler input - 1 Update
• ???The pool of talented C++ developers is running dry??? - 2 Updates

xkcd: Y2K and 2038

Lynn McGuire <lynnmcguire5@gmail.com>: Nov 11 02:29PM -0600 xkcd: Y2K and 2038 https://xkcd.com/2697/   It shouldn't cost more than a trillion dollars or two to investigate this.   Explained at: https://www.explainxkcd.com/wiki/index.php/2697:_Y2K_and_2038   Lynn

Back to top

Simulating halt decider applied to a simpler input

olcott <polcott2@gmail.com>: Nov 11 09:28AM -0600 void E(void (*x)()) { H(x, x); }   (Ignoring stack overflow) If H correctly simulates E would the simulated E ever stop running without being aborted?   Because no E would ever stop running unless H aborts its simulation of E this proves that the aborted E specifies a non-halting sequence of configurations.   Simulating Halt Decider Applied to the Halting Theorem https://www.researchgate.net/publication/364657019_Simulating_Halt_Decider_Applied_to_the_Halting_Theorem   -- Copyright 2022 Pete Olcott "Talent hits a target no one else can hit; Genius hits a target no one else can see." Arthur Schopenhauer

Back to top

???The pool of talented C++ developers is running dry???

David Brown <david.brown@hesbynett.no>: Nov 11 08:10AM +0100 On 10/11/2022 21:53, Chris M. Thomasson wrote: > implementation of std::mutex...   > std::vector<std::mutex> m_locks;   > Fair enough?   As long as std::mutex is a wrapper for a real OS mutex, that will be fine (after padding for cache line sizes).   The problem with the atomics library in gcc is not the array of locks or the hashing on address, but that it doesn't use /real/ locks.

"Öö Tiib" <ootiib@hot.ee>: Nov 11 01:45AM -0800 On Friday, 11 November 2022 at 09:11:17 UTC+2, David Brown wrote: > fine (after padding for cache line sizes).   > The problem with the atomics library in gcc is not the array of locks or > the hashing on address, but that it doesn't use /real/ locks.   Yes. Libraries look often like sabotaged and so who needs quality and portability has to use conditional compiling for what they use std::atomic<Something> and for what manually mutex-protected Something instance. Purpose defeated.

Back to top

You received this digest because you're subscribed to updates for this group. You can change your settings on the group membership page. To unsubscribe from this group and stop receiving emails from it send an email to comp.lang.c+++unsubscribe@googlegroups.com.