[Development] Using '#pragma once' instead of include guards?

[Volker Hilsheimer]

Hi,


We are using `#pragma once` in a number of examples and tests in the Qt source tree, but I don’t think we have officially endorsed it in favour of explicit include guards.

#pragma once is “non-standard but widely supported” [1], with some caveats, e.g. when there are multiple header files with the same name (which each compiler then handles differently, as there is no standard).

From what I see, it should in practice be ok to use. But perhaps I’m missing something. Does anything speak against using ‘#pragma once’ in new files?


Volker

[1] https://en.wikipedia.org/wiki/Pragma_once