https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67224
--- Comment #12 from Eric <ejolson at unr dot edu> --- I'm glad to know people like Joseph are working on UTF-8 in gcc. Last year I spent a week adding UTF-8 input support to pcc. At that time Microsoft Studio and clang already supported UTF-8 input files and I expected that gcc would do so in the next release. As this didn't happen, a few months ago I looked and developed a one-line patch to add this support to gcc. It appears the C preprocessor falls back to libiconv when it encounters a conversion not supported internally. From what I can tell this is enabled by default, though it is surely possible to disable it. I'm aware that C strings are often used to store 8-bit data, for example, to display various graphics characters from legacy code pages. I will run the regression tests as soon as possible to see what, if anything, has broken by my one-line patch. UCN quoting of UTF-8 input should happen only if the -finput-charset=UTF-8 flag is set and this is worth checking.