There actually is a bug filed against GCC [1] because it searches a linked list for headers using #pragma once and searches a hash table for headers using inclu

There actually is a bug filed against GCC [1] because it searches a linked list for headers using #pragma once and searches a hash table for headers using include guards. The performance difference is noticable for translation units that include a lot of headers. It would be a relatively simple thing to fix, if anyone is looking for a fun little project to learn a bit about GCC. [1]: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58770 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58770