@rmerriam "#pragma once" directive seems to be supported by most compilers nowadays. I've never had to use manual include guards, though again, none of the projects I've worked on are really that big.
@rmerriam True, although by "header/include guard" I meant the "old style" using #ifndef, #define, #endif etc. And yeah, pragma is definitely more convenient.
@rmerriam Could be some edge cases where #pragma once doesn't work.