https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81992
--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> --- This has been a C++ FAQ for nearly 20 years, and is even documented in our manual: https://gcc.gnu.org/onlinedocs/libstdc++/manual/strings.html#strings.string.simple Also https://stackoverflow.com/questions/7131858/stdtransform-and-toupper-no-matching-function
