How to construct a or exception without throwing?

Question

Exceptions defined in (e.g. std::logic_error, std::runtime_error and their subclasses such as std::system_erro

Answer 1

Short answer, it is not possible to construct any objects with an absolute guarantee of no exceptions.

You may consider allocating on the stack, but your thread stack could run out and will cause system error/exception. Your CPU may get an external interrupt, right when you throw, that system can't handle and everything gets fried. As others have suggested, don't fret the small stuff. Running out of memory is something most user programs can't recover from, so don't worry about it, elegantly fail. Don't try to handle every bad situation, just ones you can easily recover from.

As a side-note, for the situation about running out of memory, a lot of high graphics games do all of their heap allocation up-front during game initialization and try to avoid after the game starts to reduce running into issues with out of memory/slow allocations in the middle of a game (jittery game & bad user experience). You can similarly be smart about design of your program to reduce the chances of running into bad situations.