Comment by lifthrasiir

Note that this uses not only trigraphs but also digraphs (here `<%`, `%>` and `%:`), which are similar to trigraphs in intended usages but behave much differently to digraphs in that it is a proper token and not a preprocessor substitution pattern. `printf("??(foo??)<:bar:>%c", "quux"<:1:>)` prints `[foo]<:bar:>u`, for example. Therefore digraphs are deemed less dangerous (however obscure) than trigraphs and do not require any compiler options.