https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110186
--- Comment #2 from Amir Ansari <amir.ahmed.ansari at outlook dot com> --- The compiler is warning about B::B() = default. That is C++ 11. How can you say it has not been updated for C++11? Meyer's updated book has a slightly different name: Effective Modern C++: 42 Specific Ways to Improve Your Use of C++11 and C++14 https://www.amazon.com/Effective-Modern-Specific-Ways-Improve/dp/1491903996/ref=sxin_11_mbs_w_global_sims?content-id=amzn1.sym.f6adc278-60fd-4516-8b02-0dbae28f44f1%3Aamzn1.sym.f6adc278-60fd-4516-8b02-0dbae28f44f1&crid=2O08PJEXO1KA3&cv_ct_cx=effective+c%2B%2B&keywords=effective+c%2B%2B&pd_rd_i=1491903996&pd_rd_r=2a95b35c-be52-4f57-9146-6e8f627019b9&pd_rd_w=gW5r8&pd_rd_wg=664iO&pf_rd_p=f6adc278-60fd-4516-8b02-0dbae28f44f1&pf_rd_r=AC6GTZ4RY51196JFRGDX&qid=1686292780&sprefix=effective+c%2B%2Caps%2C318&sr=1-1-9e7645f9-2d19-4bff-863e-f6cdbe50f990
